High idle and Cruise 'idle'...

I got cha...yeah it's worth a look.

But I don't think this is my problem anymore. I am about 99% sure it's the TPS. The car acted the same today as it did the last couple time the problem has popped up, and I had my scanner in the whole time. I noted a reading of TPS 2.4% while coasting, in any gear, any speed. I did another rest/relearn process...the car started at a TPS reading of 0.0, then halfway through the problem came back. Read 3.7% at one point (no actual throttle of course) and then dropped to 1.6% and back up to 2.4%. All on it's own. I will check the sensor with my meter but I'm not sure it's necessary. Opinions?

If I do change the TPS, should I do another re-learn?

EDIT: Just did a little more reading and I noticed that apparently, the TPS will affect shift timing as well. I do recall upshifting into gears 2 and 3 the shifts being a little late. Now I'm 99.5% sure it's the TPS.

Alright new update, and I think I still need some help. This is what I just wrote over at pontiacbonnevilleclub:

The TPS was indeed acting up as stated in a previous post in this thread, so I got a 'new' one from Advance and it was bad out of the box. I put my old one back on and the car was fine for about a week. It started acting up again so I got a spare TPS from harofreak here on the board. I just swapped it in tonight and did the following:

Installed sensor (battery was still connected...oops)
Checked TPS position with my scanner...it read 0.6%
I cycled the ignition on/off twice and it read at 0.0%
Took it for a ride and the idle problem came back about a mile into the drive, with the TPS position reading 5.2% while off the throttle
Got back to the house and disconnected the battery, touched the cables together to drain the PCM capacitors
Checked the TPS again and it said 0.0%
Just out of curiosity, checked the TPS wiring again and it read +5.0v
Took it for a ride and everything was happy and dandy.


Anything else I should have done, or should do now? I was going to take the T-type to work tomorrow but I'll take this thing to make sure it behaves.

I think I'm going over some old bases here but did you log the TPS for a while and look for spikes and such already? At this point, I'd be tempted to install temporary wires to the sensor from the pins on the PCM straight to the sensor & ground as well. Just run 'em through the fender and door. I've done that to kinda just test wires once and for all. They can be bastards to find problems in sometimes.

Something similar happened to me recently. I have the riv parked for the summer and I start it and take it for a drive at least once a week.

After realizing I lost my front brakes I slowly made it back to the parking lot. Backing up alone was a bit difficult but when I put the shifter in Park the tachometer read 3000rpms and it felt like it was running too fast. I put it in drive and then back in park and it did the same thing.

Hoping not to cause a big issue a quickly turned it off and left. It was the hottest day of the week and I wanted to take it for a quick drive before it got too hot out. I didn't care to stick around in the hot lot under the sun and try and figure out things I don't know what to look for.

Any ideas? 3 months ago I replaced the TPS since it was rumbling in idle and hasn't since it has been replaced.

I am under the impression that the car need the MAF replaced or the MAF wires(scared to replace one to find the other was the problem; unemployed/ no play $$). The car did not act like this a week ago, I drove it to the gym with no problem. 'Gunning' the car a week ago resulted in it not smooth accelerating/boosting on the high end. Driving like an old man made the car feel like it had no issues what so ever.

Andysdorm wrote:

Something similar happened to me recently. I have the riv parked for the summer and I start it and take it for a drive at least once a week.

After realizing I lost my front brakes I slowly made it back to the parking lot. Backing up alone was a bit difficult but when I put the shifter in Park the tachometer read 3000rpms and it felt like it was running too fast. I put it in drive and then back in park and it did the same thing.

Hoping not to cause a big issue a quickly turned it off and left. It was the hottest day of the week and I wanted to take it for a quick drive before it got too hot out. I didn't care to stick around in the hot lot under the sun and try and figure out things I don't know what to look for.

Any ideas? 3 months ago I replaced the TPS since it was rumbling in idle and hasn't since it has been replaced.

I am under the impression that the car need the MAF replaced or the MAF wires(scared to replace one to find the other was the problem; unemployed/ no play $$). The car did not act like this a week ago, I drove it to the gym with no problem. 'Gunning' the car a week ago resulted in it not smooth accelerating/boosting on the high end. Driving like an old man made the car feel like it had no issues what so ever.

Different people mean different things when they talk about "gunning" the Riv. The Riv does not rev as high as any car with a 4-banger, and that's on purpose as part of what's done to make the engine generate a whole lot of torque at low revs. I mean, you're talking about a car that has a rev limiter set at ~4,000 in neutral and will cruise at any incline customary to an interstate at 65 mph in 4th gear at not quite 1700 rpm... Many 4-bangers are just getting interesting at 4000 rpm and unlike the Riv sure *will not* cruise in top gear uphill on an interstate without downshifting...

I mean, don't get me wrong, you may have a problem with the MAF. Just the same you have no play $$.

What I am thinking is the most important thing on the car is the brakes, you *must* be able to stop it. So effectively you're parked until you solve *that* problem.

Next thing is you may need to spend money in order to save money. It might be time to get a scanner. [NOT a code reader, you can get most parts stores to read codes for free...] You might search on this site for info on getting a used Actron or some such off eBay. I use Car-Code, a piece of software for my laptop that's free and a dongle I bought off the software author for under $200 (over 10 years ago). It' won't work with a '95, only the '96 and later OBD-2 cars. www.obd-2.com is the site if you are curious. You can get an Actron that works with the '95s.

Anyway -- If you get a scanner that works for your car then you can read what the MAF, TPS and other sensors are seeing and decide if they have problems. Without a scanner you are just guessing; you may be right based on your reckoning of others' experience but you are guessing. And more often than not guessing costs more than it pays.

Albertj

Well good news is I've got all the parts I need to replace the brakes and all the brake lines are 1 yr young and still under the 1yr service warranty if the workmanship was an issue. My brother in law mechanic said he'd help me but I'll have to remind him throughout the week so I'm not left with an unstoppable Riv while he goes dirtbike riding like he usually does.

When I say 'gun' the car I mean enjoying that feeling it once had when I'm getting on the highway and needed that pulled back in your seat power the car used to give(when traffic won't let you in). Of course I never rode hard on the car/accelerator but did enjoy the occasional boost once and awhile. But now when I feel like I'm hitting what some described as a boost, the car pulls back at a high speed, goes up a little and pulls back down again. This also happens when you push that lever under the hood that accelerates the engine.< my brother in law was looking it over months back when I was focused on the TPS sensor. He thought it was a factory limiter of sorts.

I've been looking for a OBD1.5 scanner/reader for a year now. I got an OBD2 scanner for Christmas and an OBD1 port adapter but sadly the system does not recognize my 1995 Riv. I wanted to return the unusable device and buy something that worked but the device was purchased in the Summer and the return policy is only for a month.

I don't feel comfortable getting the Riv scanned at my in-town mechanic frequently without bring it in. I just don't trust the guy but he's the only one around that is available.

If you will search on this site you'll find the model #s for the Actron scanner that will work. I do not have them.

As for gunning your Riv that's your business, I don't care but since you commented/asked I figured it would not hurt to mention that it's an issue. The 3800 is not built to be a high revving engine although it can be modified for that kind of use. Don't take it personally, it's just something to be aware of.

Well from my understanding of wear patterns on the 3800s (Dad's seen plenty of them at both their best and worst) the 3800 should be fine so long as you don't go to redline. 2000-4000 range the engine has absolutely no problems whatsoever, even in pure stock form. Engines that are revved above 4 grand on a daily basis? That's when parts begin to fail rapidly.

But I do agree that a scanner is incredibly helpful.....particularly if you have friends or family that can snag one of the GM tech scanners for a night or two

themanwithsauce wrote:

Engines that are revved above 4 grand on a daily basis? That's when parts begin to fail rapidly.

I doubt that very much. The 3800 is reliable to at least 5500 RPM. I rev my 455 to that regularly, and the 455 has an inferior oiling system. The 3800 has excellent oiling. My oil pressure is never below 60 psi from 1200 RPM and up. That's plenty of oil pressure to rev to 6000 RPM. Now if you increase boost on these engines, don't do supporting mods, and don't monitor knock retard, that's another story.

Luckily for me these 'boosts' I liked occur for me under the 4000 range; I don't push it like a 4-banger.

I guess its hard to explain the perfomance I'm missing.

But I am certain my oldman driving style is not the issue. I don't try to race people, just trying to get on the highway. This is why I returned to Riviera when looking to replace the old one. I didn't need a fast car just something that had enough power to make quick choices if needed. Here in MA there aren't a lot of courteous drivers.

Andysdorm wrote:

Luckily for me these 'boosts' I liked occur for me under the 4000 range; I don't push it like a 4-banger.

I guess its hard to explain the performance I'm missing.

But I am certain my oldman driving style is not the issue. I don't try to race people, just trying to get on the highway. This is why I returned to Riviera when looking to replace the old one. I didn't need a fast car just something that had enough power to make quick choices if needed. Here in MA there aren't a lot of courteous drivers.

I think we can make headway here if you summarize what you've done so far. A simple list will do.

While you are at it, how about this evening you check whatever part of the ignition system you have not bothered yet: spark plug cables and coils come to mind. You'll need a multimeter (well, an ohmmeter) for this - but consider checking resistance of the coils, look for around 5.3-5.6 ohms across each coil. Also consider checking the spark plug wires for physical damage - remove from each plug and coil and check the ends, look for breaks (even partial breaks) in the wire where the terminals are swaged on. You may need a penlight (small flashlight) and magnifying glass to see in the terminal. You may even want to pull each plug and check for cracks...

Let us know what you find...

Albertj

LARRY70GS wrote:

themanwithsauce wrote:

Engines that are revved above 4 grand on a daily basis? That's when parts begin to fail rapidly.

I doubt that very much. The 3800 is reliable to at least 5500 RPM. I rev my 455 to that regularly, and the 455 has an inferior oiling system. The 3800 has excellent oiling. My oil pressure is never below 60 psi from 1200 RPM and up. That's plenty of oil pressure to rev to 6000 RPM. Now if you increase boost on these engines, don't do supporting mods, and don't monitor knock retard, that's another story.

It's not the act of hitting redline that causes damage, it's the people who stomp on their engine after every stop in the daily grind that move up and down the rev range very rapidly at lower speeds (not on the freeway). By "regularly" I meant those kinds of drivers. I guess most engines fall apart after that kind of low airflow and high temperature abuse but still, just pointing out there's a difference between enjoying a moment of fun and driving like an ass.

themanwithsauce wrote:

LARRY70GS wrote:

themanwithsauce wrote:

Engines that are revved above 4 grand on a daily basis? That's when parts begin to fail rapidly.

I doubt that very much. The 3800 is reliable to at least 5500 RPM. I rev my 455 to that regularly, and the 455 has an inferior oiling system. The 3800 has excellent oiling. My oil pressure is never below 60 psi from 1200 RPM and up. That's plenty of oil pressure to rev to 6000 RPM. Now if you increase boost on these engines, don't do supporting mods, and don't monitor knock retard, that's another story.

It's not the act of hitting redline that causes damage, it's the people who stomp on their engine after every stop in the daily grind that move up and down the rev range very rapidly at lower speeds (not on the freeway). By "regularly" I meant those kinds of drivers. I guess most engines fall apart after that kind of low airflow and high temperature abuse but still, just pointing out there's a difference between enjoying a moment of fun and driving like an ass.

As long as the oil is flowing, and you don't beat on it when the engine is cold, the 3800 will take lot's of abuse. Having a lead foot will waste a lot of gas, that's about it. The kind of driving you are talking about is much more likely to damage the weak link, namely the transmission, and possibly the axles. Having said that, I have found that there really is no reason to floor the Riviera. You don't have to step on them very much to make them go, and the Riviera has great power at virtually any speed. Once it goes into boost, you can pretty much do anything in any driving situation. It is what I like best about the car. You'll see what I mean when your car runs as it should, and it will. I wouldn't worry about revving it past 4000. It makes peak HP at 5200 RPM, and peak torque at 3600 RPM.

LARRY70GS wrote:

Having a lead foot will waste a lot of gas, that's about it.

This rang surprisingly truthful to me just recently as my mileage tests just came back and I averaged ~27 mpg doing 65 on the freeway and cruising at 50 on 45 mph roads. After my friday night of stalking other racers on woodward and spending the thursday before that and the saturday after that replacing parts and fluids (engine spent about an hour or two at idle/ gentle revving to move fluids but I wasn;t driving anywhere) I got.....13! Moral of the story - holy crap can that engine drink...

But getting this back on topic - Unless you've been driving around like a bat out of hell "spirited" driving is unlikely to cause engine issues. Provided you've kept up with oil changes and checked coolant levels and battery voltage and whatnot this is more likely random failure or normal age failure than anything else. (I still maintain though that if you race to 5000rpm + after every light you'll have more problems than grandpa's riv )

Something my dad did that was pretty cool and was also reassuring was to individually deactivate each cylinder to search for "weak" cylinders and identify if an injector or coil was damaged that way. He said it worked like this - the scanner read how the engine idled over a period of time and basically set an "average" rpm reading and the expected "range" the engine revved at. Then you went through and deactivated a cylinder (makes the most sense to start with #1 but if you have a suspicion then start there). If the cylinder is working properly, the idle will fluctuate and change quite harshly as that cylinder was providing its share of power to the engine. However, if you deactivated one and it didn't fluctuate then it was a sign that that cylinder had an issue with either fuel delivery or ignition.

If this is the case then it might be worthwhile to look into and it would even tell you what wire(s) to inspect for the spark plugs. Or if you suspect fuel issues it can identify the most likely culprits very quickly.

I dont mean to be rude guys, but I think my thread got hijacked lol.

No biggie. Anyway, Turtle, I did read your advice about direct-wiring the TPS to the computer. Luckily for me, my PCM is in the engine bay, about 2 feet from the TPS. I'll try that, but I need to get a pinout first. I don't have a service manual for my Bonneville.

So what do you guys think of this: Whilst messing around with the car yesterday morning I found that if I unplugged the TPS, the car would operate normally. Well, idle normally. The scanner said before I unplugged it that it was at 6.7% open. Unplugged, 0.0 as expected. I would plug it back in, 6.7 and idle was hell. What the heck is happening here?

While talking with my one mechanic (not a run of the mill brake job guy or something but an actual competent mechanic) suggested the throttle plate shaft hole may be slightly out of round and pushing on the TPS and maybe making it stuck? Or something like that? I'm going to play with it in the morning before work to see what I can find. Maybe something is loose? I still haven't had the chance to clean the TB so anything is possible.

Z-type wrote:

I dont mean to be rude guys, but I think my thread got hijacked lol.

No biggie. Anyway, Turtle, I did read your advice about direct-wiring the TPS to the computer. Luckily for me, my PCM is in the engine bay, about 2 feet from the TPS. I'll try that, but I need to get a pinout first. I don't have a service manual for my Bonneville.

So what do you guys think of this: Whilst messing around with the car yesterday morning I found that if I unplugged the TPS, the car would operate normally. Well, idle normally. The scanner said before I unplugged it that it was at 6.7% open. Unplugged, 0.0 as expected. I would plug it back in, 6.7 and idle was hell. What the heck is happening here?

While talking with my one mechanic (not a run of the mill brake job guy or something but an actual competent mechanic) suggested the throttle plate shaft hole may be slightly out of round and pushing on the TPS and maybe making it stuck? Or something like that? I'm going to play with it in the morning before work to see what I can find. Maybe something is loose? I still haven't had the chance to clean the TB so anything is possible.

Sounds like the TB is dirty and there's a buildup of stuff by the throttle plate...

Albertj

I like that smiley Albert lol. I ordered a TB gasket last night, should be here tomorrow or Saturday.


Rain threatened today so I took the Bonneville instead of the T-type, and the car drove like a dream.

I'm confused, but I'm going to clean the TB as my next step and take it from there.

My Riv is fixed. Finally! Pop the champagne.

The MAF sensor was the be all end all of the car's issues. I will be taking it for a 100mile ride this weekend to really see if everything is undercontrol.

Summary of the issues:
-on highway with cruise on the car would have a hard time making hills.
-trying to accelerate quickly like to get out onto the highway or out of a parking lot onto a busy road usually resulted in a 'pulling back' feeling as soon as it was building power
- and of course my Check Engine light was always on.

I am currently knocking on all the wood surfaces I can find.

To make up for all the costs of trying to fix the Riv I am thinking of switching to regular gas but was always reluctant given the age of the car and I don't car to replace additional parts that will fail or dry out by using sub par octane fuel. But now that its fixed I would like it to treat me for a change and lower costs at the pump would be nice. According to the manual and YouTube mechanics training video there are systems in the car to alter the way the fuel is processed so that it can run on Regular.

I'm looking to get to 100k and then someone else can have her. But as it is, I think I'm ready for winter.

It feels great to have that stupid orange light (SES) out of your view!!

Glad you found the source of your problem. Did you try cleaning your old MAF before replacing it? Once mine was giving similar problems, a good cleaning made things like new. I'm still on the OEM MAF sensor at 235k miles.

Regarding your engine running on lower octane fuel, yes it can be done with some tuning by retarding the timing. This requires some reprogramming of the timing maps, and isn't easy to do on Series I SC (no DIY tuners are available, imo). A much simpler solution is to have an underdriven SC pulley turned by a machinist. This would lower your boost, and ultimately reduce your power/torque output to a level where the engine would run fine on lower octane gas. The most convenient way to do this imo would be to purchase an MPS (modular pulley system) that allows you to manually swap pulleys in a matter of 5-10 mins. You can then run whichever fuel octane you choose by changing the pulley - just don't forget which one's installed when you fill up!

I did buy some MAF cleaner. And it seemed to somewhat work for a moment but the issue would come back. The cleaning wasn't good enough that it made me think the MAF was THE part to replace.

My mechanic read the codes and told me it could be the sensor or it could be the wires. And having been told the wires could take awhile, I was reluctant to replace the MAF if I needed to save the money for a wiring job.

Guess I'll stick with Premium, sounds like changing it leads to additional costs for not much of a return.

Another very simple solution for running regular would be to attach a 1-2" thick block of wood or similar material to the back side of the gas pedal. All joking aside, the result would be roughly the same as swapping to a larger blower pulley, or retarding the timing. Only difference is, your pedal wouldn't go all the way to the floor using the block. Might sound silly, but there's no getting around the fact that using lower octane means having less throttle.

I bought the MAF sensor and had a week and a half of pleasureable moments driving the Riv in excellent condition...until today.

I had thought the MAF was the be all end all of my frustrations until my little friend "CHECK ENGINE" light came on AGAIN!

The setting: hellish downpours the past 3 days, back road just hit a very small imperfection in the road. Light comes on. Andy goes insane, again.


So at least now, after all the repairs, it has to be an electrical thing. I do not notice the past issues of bucking or loss of power and the light comes on eventually during driving and goes out when restarted.

After having watched the YouTube video for the 1995 Riviera mechanics training, I figure I might go ahead and remove the negative connection from the battery for 10 minutes to 'clear out' all the old codes and return the computer to burn my fuel like before without having to compensate/recalculate a different combustion setting(from what I heard from the GM video).

Besides that I don't know what the next step could be to locate the faulty wiring or piece that got jarred loose throwing off a code to the computer.

Damn, and I was even considering getting an inspection done 4 months prior so I wouldn't have to worry about it in December.

Andysdorm wrote:

I bought the MAF sensor and had a week and a half of pleasureable moments driving the Riv in excellent condition...until today.

I had thought the MAF was the be all end all of my frustrations until my little friend "CHECK ENGINE" light came on AGAIN!

The setting: hellish downpours the past 3 days, back road just hit a very small imperfection in the road. Light comes on. Andy goes insane, again.


So at least now, after all the repairs, it has to be an electrical thing. I do not notice the past issues of bucking or loss of power and the light comes on eventually during driving and goes out when restarted.

After having watched the YouTube video for the 1995 Riviera mechanics training, I figure I might go ahead and remove the negative connection from the battery for 10 minutes to 'clear out' all the old codes and return the computer to burn my fuel like before without having to compensate/recalculate a different combustion setting(from what I heard from the GM video).

Besides that I don't know what the next step could be to locate the faulty wiring or piece that got jarred loose throwing off a code to the computer.

Damn, and I was even considering getting an inspection done 4 months prior so I wouldn't have to worry about it in December.

OK, the CEL's on, what's the code?

I have no idea about the code. Its a 1995 and my OBD1 and OBD2 readers are useless.