Crank-no start....even the local shop threw in the towel

My very dependable 95 s/c Riv left me stranded
Towed to shop....fuel pump replaced
1 week later....stalls at light...crank-no start...towed
Shop has Trouble diagnosing cause of the obd 1.5 situation....no old time equipment so they had to rely on old school diagnosis....put in known good ignition module....still no start....put in new crank sensor....it starts
I pick it up drive it for 3 weeks, it was parked for one...get in ......crank-no start .....no ses light on
Towed back to shop....they had it 3 weeks then called to politely say maybe I should think about getting a newer car they can't fix it
I've got the gm mauals for it....do not have access to an oscilloscope as I was told this would make more of a definitive diagnosis...I have the actron 9145 code reader but as I said ses not lit
BTW fuel pressure is good....anyone help me with a list ....in order....of what I can do to check for power, ref. signal, grounds...etc etc , I'm going old school here cause I know it can be done
Thanks Mark

I had a similar problem on my 98, turned out the new Standard brand crank sensor I'd installed had quit.  Use a good (not necessarily expensive) one like Delphi, WVE or NTK.  

The other thing - on the 95s there was a problem with the wire bundle on the ignition module and at the firewall.  It is documented in some detail elsewhere on this site.  What you're looking for in both locations is a wire that has broken off inside the insulation. Check them one by one, by wiggling at the connectors (yes it is tedious to do but you've really no choice).   Fix is to prise out the corresponding pin and install a new one on the wire; maybe splice a small length of new copper wire on that end there to go to the connector pin.  My guess is this most likely was the problem all along, or in conjunction  with the crank sensor (which when it fails sets no code whatsoever).  What happened: On many of the 95s, over time some of the copper in that wire bundle work-hardens and depending on other things will snap apart inside the insulation.  Then it will work intermittently and drive you batsh-t crazy.

Thanks Albert...you're always a help....yes that's what it usually is corroded and/or broken wire....just trying to isolate where the problem lies...I failed auto electric back in the day...getting better though ....all I have is the test light and multi meter ....I have the scan tool actron 9145 but there are no codes present or stored....so can you tell me where I'm checking next?...spark, injector pulse...

The gm riviera manual assumes that we are "techs" with the computer lap tops and alot of the tests in them require the unit....but I know we can get by with out it

albertj wrote:

I had a similar problem on my 98, turned out the new Standard brand crank sensor I'd installed had quit.

As much as it sucks, this is a strong possibility with the supply chain problems we've been having over the last year or more. Getting a good part is a crap shoot these days. This is particularly awful in the case of the crankcase position sensor, which isn't such an expensive part but GM had to make it impossible to remove without pulling the harmonic balancer. I hope your shop knew not to reuse the original harmonic balancer bolt.

I don't know Jack....I'm afraid to look....the kids they have in there.....don't even know what a v.a.t. system is....or that they could access the fuel pump through the trunk....can they get the crankshaft sensor off without removing it? I've never changed one but I would because I know the manual says to remove it....

I don't know Jack....I'm afraid to look....the kids they have in there.....don't even know what a v.a.t. system is....or that they could access the fuel pump through the trunk....can they get the crankshaft sensor off without removing it? I've never changed one but I would because I know the manual says to remove it....

OBD1.5 wrote:

Thanks Albert...you're always a help....yes that's what it usually is corroded and/or broken wire....just trying to isolate where the problem lies...I failed auto electric back in the day...getting better though ....all I have is the test light and multi meter ....I have the scan tool actron 9145 but there are no codes present or stored....so can you tell me where I'm checking next?...spark, injector pulse...

There is no shame in failing auto electric, the only shame is in quitting and to fix this problem, you're going to have to get back in the saddle, buck-o. Fortunately, there are good instructions for this old-school troubleshooting.  

So, wihtout further ado, here's one reliable way to  check for a broken wire.  Warning - NO shortcuts. No skipping inconvenient steps.  Just follow the instructions.  There is no scan tool that will do this for you if only because broken wires don't generally set codes.  If they did, then every time you flipped a friggn' switch, you'd set a code.  The only thing they *don't* tell you in these instructions is (1) that sometimes you can strip and solder the wire to repair it and (2) that you should  paint liquid electrical tape over the pinholes after you are done troubleshooting and you pull the pins, especially if your wire is in a moist or oily environment.

Why do this? You've already thrown a number of parts at this problem and it's still a problem - that's what you know. If you do this now. you'll eliminate a known point of failure that your scanner won't tell you.

So, for this one you can put your Actron back on the shelf. Happy hunting.

-end-
https://itstillruns.com/check-wire-broken-8377628.html

Thank you Sir .....much appreciated for the directional help.....got to PUSH this turkey into the garage before old man winter gets here so I can begin dissecting it

OBD1.5 wrote:

Thank you Sir .....much appreciated for the directional help.....got to PUSH this turkey into the garage before old man winter gets here so I can begin dissecting it

If it's above freezing out, you should be able to find the broken wire(s) if any there is one just by physical inspection.

I'd appreciate it if you read through the following thread. It will take a while. However, it's also got photos showing the more or less common wiring problem on the early 8th gen Rivs. Larry and I went around the barn a little on this one - when he found it was indeed the problem he did an **excellent** write-up. Which you should read. It's at the end of the FAQ thread linked below.

https://rivperformance.editboard.com/t4703p200-faq-p0341-camshaft-position-sensor-cam-sensor-timing-chain?highlight=cam+sensor+code

-end-

I'm trying to upload a picture of what I discovered while doing a basic examination

Zoom in on the middle left wire.....lt blu/wht....that is crankshaft sensor imput signal wire....without this info no spark no injector pulse....I think I might have found problem....need to confirm

OBD1.5 wrote:

Zoom in on the middle left wire.....lt blu/wht....that is crankshaft sensor imput signal wire....without this info no spark no injector pulse....I think I might have found problem....need to confirm

You seem to have many problems at that ig module, not just the chafed blue/white wire.  Check (and repair) all the wires.  And remember to check the block at the firewall like in Larry's write-up.  

The good news is that once this is fixed right it's a once and done job.  Trick is to fix it right 'cause if you don't, the problems will continue indefinitely.

And just to stir things up I'll end with this:

*Exactly why didn't the paid, trained mechanics find this problem? It's right out in front of the engine!?!?!*

Yes I've read Larry's write up before.. very good one...another thing I've discovered is po had a remote car starter...I didn't know this....notice the connector on the white ignition control wire...under the dash panel is a mess of cut and taped wires.....oh boy

OBD1.5 wrote:

Yes I've read Larry's write up before.. very good one...another thing I've discovered is po had a remote car starter...I didn't know this....notice the  connector on the white ignition control wire...under the dash panel is a mess of cut and taped wires.....oh boy

It's not a disaster, you have choices. If you have a little time on your hands you can probably get a harness that is not hacked for short money, from any of the pick and pulls that has a same-year Riv they are letting people dismantle. One way to find them is row52.com - it's a network of independent pick-and-pulls, and of people who earn cash going to those yards and pulling parts for other folks. I have not looked lately but it is nationwide and you're likely to find what you need and someone to snag it for you. Even just the connector and first foot of the wiring could work, you can splice it in or move teh pins with good wires from your old harness and splice in the others some distance away from the high vibration environment near the connector.


Second alternative is repair the harness you have using a kit of GM pins, maybe something like this: https://www.amazon.com/Pico-0003og3-Gm-Terminal-Kit/dp/B001QRTVZQ - it's a little tedious but not terrible. The reason for using a dealership is that if there is a mechanic there who'll repair the wiring, they should have access to a kit like this: https://gmtoolsandequipment.com/en-US/Pages/ItemDetail.aspx?SKU=J-38125-H - between this and spools of wire that match the harness they'll likely be able to restore it not just repair it. Use your best judgement...

Yes we have some of the pick n saves up here....they're on the nationwide network....I've had a hood and fender delivered 4 hours away for $65 placed in my driveway....what a deal.....funny you should mention the new connector kit....I was on rock auto as your update came in....80.00 gets you the connector with new wires already assembled and and heat shrink butt connectors....I'm feeling good about it...once again thank you for your direction and help....amazing

Well I did a continuity test on all 4 wires from the crank sensor connector to the ign module connector and there are no breaks in the wires for flow.....I've now taken off the ignition control module as an assembly and will inspect inside the wiring harness that houses all the wires for obvious signs of damage or degradation

OBD1.5 wrote:

Well I did a continuity test on all 4 wires from the crank sensor connector to the ign module connector and there are no breaks in the wires for flow.....I've now taken off the ignition control module as an assembly and will inspect inside the wiring harness that houses all the wires for obvious signs of damage or degradation

Did you move/wiggle the wires while testing and/or look at them to determine if any of the conductors were fractured inside the insulation?

A wire broken inside the insulation is *not* obvious.

Yes I did Albert....no change...

Here is the problem child right here. Circuit 451 blk/WHT. Terminal K , ignition module ground wire to G101 @cylinder head ....no continuity...eyelet basically fell right off

OBD1.5 wrote:

Yes I did Albert....no change...

OK

Keep at it, you'll pass Auto Electrical yet. Proud of you, this troubleshooting is an acquired skill.

Thank you Sir....my plan is to eventually undo, inspect and clean every major Ground location on this car.....I have the Riviera "Bible "...it tells you exactly where they all are

do yourself a favor, find the rest of the broken wires first (since you know where the grounds are)

Great news Albert.....she fired up on a 1/4 revolution .....thanks for your help through out the diagnosis