Update:

Now I'm starting to get frustrated.

I pulled a second plug to make sure I was getting good spark. The plug looked great and there was spark.

I checked the resistance on all 8 injectors and they were 12.2-12.4. Using a noid light I checked all 8 connections and they are pulsing properly.

I hooked up the fuel pressure gauge and it gave a pressure of 42. After 30 minutes the pressure only dropped 6 or 7 psi. Not perfect I know but they say in other posts that a pressure drop of 20 psi in less than 20 minutes is significant. I would think it is holding well enough to start the car ruling out the fuel pump and leaky injectors.

I'm not sure where that leaves me. I've got spark and the engine ran momentarily with ether. I take this as my problem is not with spark but with fuel. Although I've got good pressure at the rail and the injectors are working from an electrical standpoint. Is it possible that although the injectors are being pulsed they are not actually firing?

I'm not sure where to go next. Any suggestions?

 

Yes, I had that same issue: Had good spark......injector ohms all checked out OK....had proper fuel pressure all the way to the injectors....injector pulses were there from the ECM.... could manually fire each injector with a stand alone injector/harness tester and gas would flow through them when triggered...car would start/run only on ether only.

Long story short.... inside the fuel injector the coils were shorting out to themselves (effectively reducing the number of coil turns and strength of the solenoid effect) with ECM's voltage applied.....a voltage source that would/could pass a higher amperage to compensate for the coil turn loss (stand alone injector tester)would trigger them. Replaced the "old injectors" with new injectors and car started right up.

 

The fact that it ran on ether points to just that

You have spark and pressure but no fuel to the cylinders. I had several injectors go bad spontaneously on my original 91 L98 but it still ran on a couple of cylinders. The question to pose is "could all go bad at once?"

If you are getting electrical signal and it ran on the ether it seems that the injectors themselves would be the culprits.

 

Engle1147, It seems you had the exact same problem I have. Is there any way that I can confirm this problem with the injectors aside from replacing them all?

Also what injectors did you use as replacements?

 

I just went through similar issues with my 96 vette. Mine ended up being water in the fuel. Have yet to figure out how it got there but never the less there was alot of water in my fuel tank.
In the end after getting it going it gave me a P0300 code. It had a definate miss in it.
I pulled the fuel rail off to inspect the injectors. They were a mess!!!! Some even had rust on them. I replaced them with bosh from FIC that advertise's on here. The car purred like a kitten afterwards for about 2 days and now one of the bosh injectors has failed. I'm hoping they will replace it for me.
Sounds like your having some of the same issues I was having.
Pump some of your fuel off of the fuel rail into a bottle and see if it seperates into 2 colors, this will tell you if there is water in it. Also as you turn the car over listen to each injector by way of long screw driver to see if they are actually firing. You will hear them click. There is a possibility that some of them are not firing. Thats what mine were doing before I replaced them and it did flood the car.

 

You can confirm it by getting hold of an oscilloscope and watching the injector's pulse (info on Injectors wave forms:http://www.automotivetestsolutions.c...rWaveforms.htm)

Well if you have the stock Multecs in there you need to get those things out and put them where they belong...in the trash! The CF is full of nightmares about Multec. I went back in with a set of Ford Bosh 22lb injectors....I'm very happy with them. As far as where to buy your injectors I'd get with Jon with FIC Injectors......his links are in the "Sticky" posts at the top of the C4 Forum page.....he can point you in the right direction for injector selection.

 

I spoke with Jon directly today. He was a great help. I have a set of injectors on the way next week.

Of note, for the past year or so my engine has been running a little hotter (10-15 degrees F) and my mileage has been surprisingly good (30 US MPG @ 75 mph). I didn't make much of it but maybe I have been running lean with a couple of bad injectors and now another one has gone and that is why it won't start?

I will try the screwdriver test once I can get someone to give me a hand with cranking while I listen.

When it cranks it sounds like it almost wants to start sometimes and just can't make it over the hump. Hopefully the injectors do the trick. If not I will be very stumped.

 

mine sounded the same way. just almost but wouldnt start. bet it is the injectors.

 

Did you ever check the fuel pressure?

 

Yes, the fuel pressure was about 42 and it held quite well. Not perfect though. After about 30 minutes it was still around 36psi. Should be good enough to start the car though.

 

Any resolution here ? I am having close to the same problem.

Thanks.

 

No update yet. Still waiting for the injectors. They will have to clear customs so it might not be until early next week when I get them. Hopefully they will be here by the weekend though. I will post my results.

 

Just got the injectors from Jon and installed them. The old injectors didn't look that bad when I took them out but I know they were still on the edge of acceptable (12.2-12.4 ohm).

Unfortunately the car still won't start. It cranks and wants to fire almost and then occasionally diesels after cranking. Nothing seems to have changed with the new injectors.

Thoughts???

Could the timing belt have slipped? Could it still be the opti?

 

pm sent

Jim

 

Is it possible you just got a bad tank of gas? I think your fuel pressure is good, not a bad drop in pressure at all. I also believe you've proven it is a fuel problem because it fired and ran on starting fluid. Now you have new injectors and it still won't run, you used a noid light and saw the injectors pulsing. Bad fuel is the only thing I can think of. When it started on starting fluid was there any back firing?

 

Well I finally got it started today!! It was great to finally get it home from the parkade at work. It is running now but runs like crap. I'm just glad it is running. I will look at things this weekend to figure out what is actually wrong.

What I did tonight was just bleed the fuel rail to remove any air that might have gotten in while I was installing the injectors. If fired up after about 6 attempts of cranking. Thanks Jon for telling me about this step which I missed the other night.

So in summary the only thing I did was replace the injectors. It still isn't running perfect though so I am not comfortable saying that was the only problem just yet. Thank-you everyone for all your help.