2.8 Won't Start After Running For a While (Page 1/2)
stark86 JUN 13, 11:20 PM
Let me just preface this by saying that my Check Engine Light bulb does not work, and I do not have an OBD1 scanner (I'm looking for one if anyone has any suggestions). I have a new Fuel Pump, Fuel Filter, and Pickup coil.

I've been planning to go to Carlisle but haven't taken this car on anywhere beyond 50 miles, so my friend and I decided to take a longer road trip--About 100 miles--To stretch her legs out a bit. We hit the road, and about 30 miles in my CEL light comes on. Everything else in the car felt fine so we just decided to ride it out.

About 70 miles in, we stopped at a store, and after turning the key, the car started, and died about a half second later. Successive attempts to start the car yielded nothing. I had a spare ICM so I installed it--No dice. After about an hour of examining the engine and making sure everything was connected properly, the engine started up, albeit with a jumpy tach (engine didn't sound bad). We hit the road and reached our destination, staying there for a few hours.

On the way back, about 2 miles in, we stopped at a gas station, and the same issue happened. Needless to say the next hour was miserable and we didn't make any stops on the way back.

A few days later, the tach is still jumpy and the problem reproduces itself after a mile, but without the CEL light. I'm going to make sure all cylinders are firing, but does anyone have any suggestions as to what to look at?

Thanks

[This message has been edited by stark86 (edited 06-14-2023).]

Patrick JUN 14, 12:06 AM

quote
Originally posted by stark86:

Let me just preface this by saying that my Check Engine Light bulb does not work... about 30 miles in my Service Engine Soon light comes on... and the problem reproduces itself after a mile, but without the SES light.



Okay, I'm confused... does your CEL function or not?
stark86 JUN 14, 12:19 AM

quote
Originally posted by Patrick:

Okay, I'm confused... does your CEL function or not?



Wow... Just checked my owners manual and I guess it does appear that "Service Engine Soon" IS the Check Engine Light and they aren't separate lights. I just assumed my CEL was out because I didn't see "Check Engine" light up when I turned my key to run... Time to make some edits.

I've only had a Fiero since February, go easy on me guys
armos JUN 14, 07:19 AM
When the car won't start, does the tach come up or just sit on 0?

When you say the tach is jumpy, does that correspond to the engine or do you think the tach is wrong when that happens?

You can check error codes with a paperclip:
https://www.fiero.nl/cgi-bin/main.cgi?ECMCodes
Dennis LaGrua JUN 14, 09:42 AM
All no start problems mainly come down to fuel and spark. Could be intermittent coil operation, a bad sensor or even a defective ECM but in your case it sounds like a defective tach filter shorting out. They are very easy to replace. If you can get the car over here (Neshanic Station) and are close to Somerset or Hunterdon County, I will be happy to do a complimentary scan for you. If you can make it to Carlisle you'll absolutely love that show; 100+ Fieros, tools, books, parts, accessories, and over 1000 classic GM cars to see.
Events going on all day.
------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 06-14-2023).]

Vintage-Nut JUN 14, 10:16 AM
FYI Only
The ignition key has a momentary connection just before hitting "Start" called the "Bulb Test" position.
This momentary position shows warning bulbs/lights are functional, like the 'Brake' or 'Check Engine'

If any warning bulbs/lights aren't functional, of course first check the bulbs....
stark86 JUN 14, 11:08 PM

quote
Originally posted by armos:

When the car won't start, does the tach come up or just sit on 0?

When you say the tach is jumpy, does that correspond to the engine or do you think the tach is wrong when that happens?



Tach comes up when trying to start... Engine sounds fine so I'm thinking the tach is wrong.



quote
Originally posted by Dennis LaGrua:

All no start problems mainly come down to fuel and spark. Could be intermittent coil operation, a bad sensor or even a defective ECM but in your case it sounds like a defective tach filter shorting out.



It didn't occur to me that a shorting tach filter could be inhibiting the ignition... Since I got the car the mount has been missing so whoever messed with it before me stuffed it behind the coil, probably exposing it to a lot of heat.

I also did the paperclip method to read the codes and only came up with a code 32 (EGR Circuit Error). I'll order a tach filter from TFS right now and hope for the best.

[This message has been edited by stark86 (edited 06-14-2023).]

stark86 JUN 15, 07:53 PM
So after inducing the issue by letting my car idle in the driveway for 20 minutes and then shutting it off I unplugged the tach filter to no avail. What I did find out is that it'll run on starting fluid... I should've done this days ago.

A few hours later, I got a fuel pressure gauge and hooked it up to the Schrader valve at the top of the engine. Fuel pressure looked fine at 40psi. After turning the ignition off and back on 20 minutes later, the pressure drops and the engine quits. I don't hear the fuel pump when the key is in the "Run" position.

I have a brand new fuel pump and sender from TFS, and I've never ran the car below a half tank. Does this tend to happen on failing fuel pumps?
Patrick JUN 15, 08:11 PM

quote
Originally posted by stark86:

A few hours later, I got a fuel pressure gauge and hooked it up to the Schrader valve at the top of the engine. Fuel pressure looked fine at 40psi. After turning the ignition off and back on 20 minutes later, the pressure drops and the engine quits. I don't hear the fuel pump when the key is in the "Run" position.



Do the test this way. Jump terminal "G" at the ALDL connector with 12v from the cigarette lighter to run the fuel pump and see what happens. I believe this bypasses the relay.




What is the reading while the pump is running... and how quickly does it drop when the power is disconnected?

[This message has been edited by Patrick (edited 06-15-2023).]

Mickey_Moose JUN 16, 11:09 AM

[This message has been edited by Mickey_Moose (edited 06-16-2023).]