BaysideC4

My 1990 C4 won't start, first time in 8 years I have had a problem like this.

Ths battery is fine and it sounds like it's trying to start but nothing. I think I can eliminate the alarm as I replaced it three years ago with a brand new unit. I am thinking Fuel Pump or Coils (based on Adrians book). Is anyone an expert on this? Thanks

Shaun Leahy

Sounds like the CLASSIC DME relay problem, where everything sees to work but the engine will not catch; often this relay prevents the pump working. Any Streather book or relevant website will tell you where it is: in the 993 the relay is in the front right side of the forward luggage compartment.

I had this problem recently in my car and years ago in a 964. Replace this one relay and you will be amazed that the engine starts up fine again

BaysideC4

I'm sorry, I should have stated I did try my old (working) DME relay and it didn'"t help. I also did the cap and wires a few years ago.

BaysideC4

The battery is new also and the car ia always on a trickle charger.

jimq

can you hear the fuel pump running when you turn on the ignition?

BaysideC4

It's hard to tell. My C4 has a very loud brake boost pump too. I understand that the fuel pump is on the right side near the passenger door. I wasn't able to hear anything from there but I do hear a loud electrical sound coming from my engine compartment on the right side. It gets louder after the first 30 seconds or so then shuts off. I never noticed it before and I'm not sure if its related.

jimq

its on the drivers side on my C2. Look for a small cover that comes off in the skid plate. Maybe C4 is different.

biggles

Not sure if the sensors are issues on these cars, but with my 951 similar symptoms were the result of a bad sensor (reference/speed) wire. Good luck

biggles!

Millemiglia

My car broke down a couple of years ago. It was towed to the dealer (OPC) where they diagnosed it to a faulty clock, after replacing it with a new one, the car was running smoothly again...

BaysideC4

Are there two fuel pumps (front and rear)? My PET shows two but everyone seems to discuss the front one.

Front 964 620 104 00
Rear 930 608 113 00

I was also thinking of picking up some starter fluid to see if I can get it to turn over, has anyone ever done this?

I actually have a new front pump that I picked up at a swap meet a few years ago. I will change it out this week to help eliminate possibilities (the current one is probably original).


I have had the car for seven years, this is what I know was done –

DME – Validated with a spare = ok
Alarm/immobilizer – new one installed three years ago
New Battery – one year ago
Clock repair done to fix airbag light (all connections re soldered) – one year ago
Coils – most likely original
Fuel pump – most likely original


Thanks

BaysideC4

I got it started and I have no idea what I did to fix it, I will try it again tomorrow to see if it starts cold.

I used some starter fluid and didn't have much success. Once it sounded like it was going to start but all other times I cranked it - nothing.

I unplugged and tried my backup DME, nothing. I removed and checked the fuses for the fuel pump and DME, they were fine. In the engine area i pushed on a few connectors, everything seemed fine.

I tried to start the car again after about 10 minutes of poking around and it started to turn over. I need to give it some gas while cranking it and it started. Some gray smoke came out and disappeared quickly. I was able to take it for a quick run and I stopped and started it a few time - no problem at all.

I'm not sure if the ether helped or not. Any ideas?

BaysideC4

Cold started it today, started right up. Not sure what happened or what I did to fix it (if it's fixed).