IcantDo55

iTrader: (11)

Picked up a 70K 1995 5spd car. BONE STOCK. Wont stay running. When ya turn key it starts right up than dies a second later. Will continue to run in either. Dash displays no tach signal at all.
Replaced fuel pump (did not think it was issue but I had one) and verified pressure. Replaced CAS and Coil pack.
From my searching I read the 94-95 tach signal was sent from the coil pack to dash and ECU and if ECU does not see tach signal on startup it shuts down fuel injectors. Sounds like my issue. Now how do I verify and fix it?

It is a 4 pin coil configuration.

Thx!

IcantDo55

iTrader: (11)

So pulled out the ECU and pin 2L that I believe should be a tach signal has no wire on it. Should be B/W I thought. From this I found.

IcantDo55

iTrader: (11)

Just noticed this ECU got paint pen on it. Could is be for a different year? Is this an ECU for a 3/95 build car?

Braineack

iTrader: (62)

no tach is probably a faulty ignitor.

does it run with FP jumped?

IcantDo55

iTrader: (11)

Yes. Fp jumped did not help. It's shutting down injectors after it starts. Where the ignitor on the 1.8? Not where the 1.6 one is.

IcantDo55

iTrader: (11)

Think the ignitor is in the coils in the 1.8s?

Braineack

iTrader: (62)

test ign- to ground and see if it's faulted to ground. it shouldn't be -- if youre in diode test mode (beeps), then you should hear it rapidly pulse like that when running/cranking. if its solid ground that's an issue (maybe issue in the tach itself?)

but you said you replaced the coilpack, so that should have fixed the no tach issue.

Midtenn

iTrader: (15)

Check the ground on the front of the head on the intake side. I used to have an issue where the nut would back off and I would loose tach signal and the engine would sputter.

SpaceYeti

Also check the crossover tube for cracks. I had a similar issue and the fix was just a new crossover tube, it would start up just fine, the die right after,I could keep it alive if I kept giving it throttle. My crossover tube had a hole in it on the underside of it, and since it was after the MAF it treated it as un-metered air. Sometimes the most annoying issues are the simplest! Good luck.

Braineack

iTrader: (62)

a 95 wont be as sensitive to that. the main issue a leak like that causes the afm flapper to close, and thus cuts off the fuel pump.

SpaceYeti

Ok, good to know.

IcantDo55

iTrader: (11)

Thanksgiving over back to this project.
So I now have swped in two known good 94 coil packs and a known good ECM.
Still same thing. Starts like normal and 2 seconds later ECU cuts off injector pulse.

I read somewhere that in 94 95 if ECU does not see tach signal it pulls injectors to shut down motor.

Is there a way to test tach signal at the ECU?
How
What wire off coil pack could I jumper to ECU to see if the wire broken somewhere?
I know this 3/95 build used a 4 wire coil pack but Intresting enough the plugs that come into coils only have 3 wires in them..?

Braineack

iTrader: (62)

i think you have a 95.5 then.

see #7

IcantDo55

iTrader: (11)

It's a 3/95 build should be early 95 and 4 pin. But I did try a 3 pin and made no difference. Same issue.

Anyone with a 94 early 95 can verify if the coils have 4 wires to plug or 3?

Braineack

iTrader: (62)

Can you test ig- to ground?

SpartanSV

A DMM set to AC voltage should show something like .6-1.0 volts for a tach signal at idle.