My 1st question

My question has to do with the lag when accelerating, is this just how this engine does? When I hit the gas the engine revs to about 4500 before it shifts from 1st to second. If I ease on the gas it shifts around 3000. Why the longer shift when I get on the gas? Other than that I am happy with my car. Just seeing if there is something that I can do. I have had the car for a month and have not change the plugs or wires yet. Its a 1997 N/A buick Riviera with 174000 on the clock.

RvieraRider wrote:

My question has to do with the lag when accelerating, is this just how this engine does? When I hit the gas the engine revs to about 4500 before it shifts from 1st to second. If I ease on the gas it shifts around 3000. Why the longer shift when I get on the gas? Other than that I am happy with my car. Just seeing if there is something that I can do. I have had the car for a month and have not change the plugs or wires yet. Its a 1997 N/A buick Riviera with 174000 on the clock.

Electronically controlled transmission allows the engine to rev higher before shifting when you get on the gas to keep you in the power band - however, the gas used by the v6 when accelerating hard is, well... prodigious. If you do it long enough you can notice the gas gauge pointer move perceptibly. Without going into detail (or reciting the service manual and not telling you), the transmission's control strategy is optimized for economy in cruise control mode and not much anyplace else. What's more, the shift pattern is adaptive. That is, if you often stomp on the loud pedal, the transmission will "learn" to let you rev higher than standard before shifting, all the time not just when you are mashing the throttle. You will have to disconnect the battery + terminal and touch it to the - for a while (15-30 minutes) to force it to forget those settings (don't do that if your Theftlock is on or else your radio will quit... reset instructions are elsewhere on this site).

So...

although you CAN do that, is it important enough to actually do?

To learn more about the transmission's shift strategy, search on eBay for a factory service manual. Buy it and you'll see - lots of stuff is explained there.

And welcome to RivPerformance.

Albertj

Thanks for your reply Albert. So to sum it up. When I give the car a little extra gas standing still I will just have to endure the delay in acceleration. I'm not saying the trans is the problem, but I just wanted to know from other owners was this common. My experience with other cars that used the series II engine was that when you give it some gas, tires spin and you fly right by the next guy. So far with my riviera no tire spins and if the other guy gives me a second or two head start then I fly by him. I just wanted to know if it something I should check or was this how the car operated normally.

On any car, the shift points will vary with throttle angle. At minimum throttle, the transmission will shift through the gears quickly. At wide open throttle, the engine will wind out to near redline. Even my 70 GS will do that. With minimum throttle, I can get it into 3rd at 22MPH. At full throttle, the engine will go to 5500 RPM before it shifts. The 1-2 shift occurs around 43 MPH at that RPM.

It sounds to me as if your engine is sagging or it is hesitating. The 3800 engine is very responsive if running right.

Hesitating would be a good word for it. I give it the gas and it takes a second or two to engage. I change the fuel filter and air filter. Is there something else I should look into to help with this problem.

What year is your car? Is your service engine light on?

It sounds like there is a problem. All of the other 3800s N/A or S/C I've dealt with rev immediately when you stab the throttle.

Likely suspects: vacuum leak, MAF sensor, TPS sensor, plugs and wires... This does not mean you should replace any of these items until you have the car scanned for trouble codes and sensor outputs.

Thanks for your reply Derek. The car is a 97 N/A with no check engine lights what so ever. I hooked it to 2 different scanners to check.
I want to take a look under the hood but its been raining like cats an dogs. I was thinking it could be the plugs or wires, but they will have to wait until I get paid to get changed. I was just wondering was this common for this car.

Hope that rain comes straight North! Unusual drought conditions in NYS.

You can have it Sean we have had too much this week.

RvieraRider wrote:

Thanks for your reply Derek. The car is a 97 N/A with no check engine lights what so ever. I hooked it to 2 different scanners to check.
I want to take a look under the hood but its been raining like cats an dogs. I was thinking it could be the plugs or wires, but they will have to wait until I get paid to get changed. I was just wondering was this common for this car.

Clarifiaction: You are not scanning to read codes.

Scanning probably means to use a device that shows you the actual readings of the car' various sensors, and some information telling you what those sensor readings should be in one or another state of operation. Actron and others make scanners if you can't get access to the GM "Tech II" device. I use www.obd-2.com (Car Code).

Thanks. I guess I should have said I used 2 code readers. Does anyone else experience a lag in acceleration when you hit the gas or is it just me?

RvieraRider wrote:

Thanks. I guess I should have said I used 2 code readers. Does anyone else experience a lag in acceleration when you hit the gas or is it just me?

Have you ever removed and cleaned the throttle body and Idle Air Control?

RvieraRider wrote:

Thanks. I guess I should have said I used 2 code readers. Does anyone else experience a lag in acceleration when you hit the gas or is it just me?

I'm sure you are not the only one who has an engine that is not running right , but that is in no way normal. The 3800 is a snappy engine, N/A or SC. When it is running correctly, it will impress you quite a bit.

albertj wrote:

Have you ever removed and cleaned the throttle body and Idle Air Control?

No not yet. I will look into getting it done soon.

RvieraRider wrote:

albertj wrote:

Have you ever removed and cleaned the throttle body and Idle Air Control?

No not yet. I will look into getting it done soon.

My guess (at this time) is that you have "deferred maintenance" to catch up on. There is probably not one thing that is causing your problem. It could even be that the throttle cable was removed/replaced but now needs to be adjusted. I can't tell sitting here.

Funny you should mention that. I just noticed the throttle cable the other day. I will take a picture when I get off so you can see it.

Here's the throttle cable. As far as I can tell everything still works fine, but it looks like the previous owner rigged it up

RvieraRider wrote:

Here's the throttle cable. As far as I can tell everything still works fine, but it looks like the previous owner rigged it up

I thought that might be a problem.

With the car off, have a buddy step on the gaspedal while you watch the linkage. See how it behaves. I bet it's loose.

You have idea why it's rigged like that?

For the rest of you: The cruise linkage is spring loaded and has some play on purpose so that when the servo engages it has a little delay and so that the servo can not override the driver's input so easily. With RIvieraRider's complains I was suspecting the throttle and CC cables might be reversed - it should not be the case because the mounts are different sizes and have different heads, but like anything else it can be done. I kinda wondered if a cable was replaced and the cables reversed at that time.

Now that I see that it's "rigged" I wonder if it's the right accelerator cable to begin with, or if it's mounted wrong somehow.

Probably the thing to do if you need a replacement, since it works more or less, is to call Ed Morad and have them take the whole thing (the bracket and both CC and throttle cables) off the next Riv they get in. Maybe offer $15 for the cables and bracket?!?

Details: there were 3 CC cables - 25615098 for the sc 95, 25617543 for the na 95, 25645398 for every other. There is a retainer 15567924 shown for the 95 cars. for throttle, 25607138 for the sc 95, 25625373 for every other. In the GM data the cables probably both show up on the explosions (the diagrams) for the cruise control. Reason the 95 differs is that it had the old vacuum servo for cruise, the later Rivs all used electronic servo.

In either case I think the throttle cable should go on the left but don't quote me.

The 3800 linkages were similar to the best of my knowledge, probably easiest thing to do is find a repair garage with one or more such cars in for service and compare them side by side, or go to a junkyard where they have one or more in with the engine and TB and what not still in and take some pictures. You can use the part numbers (I think I got them right) to find replacements if you need any. Here is a site with some diagrams:

http://parts.nalleygmc.com/products/CABLE-Accelerator-Control/3015985/25625373.html

My current guess (might be BS though) is the throttle cable was replaced for some reason with a similar but incorrect unit. It also could be that it's supposed to be tied down someplace else in the engine compartment and it is not, so that when you step on the gas what you are feeling is way too much slack in a cable that's flopping around. That may become apparent when you look at what happens when you buddy steps on the throttle. Pulling the cable in the engine compartment is not gonna tell you jack about this problem, you need an assistant.

Anyway, you might end up going to a local or online dealer (and waiting for it to be shipped from Martinsburg or wherever) for the right one. But again that's just a guess.

Albertj

I will get my lady to help me with it today when I get off today.