95 gt running on four cylinders

[Mike2361]

I been searching all over the net for help on this but can't find anything so here it goes.
i have a 95 gt running on 4 cylinders I have spark and good compression. But 3,4,5,7 won't fire. Iv replaced all fuel injectors so I assume I have good fuel. Some friends are trying to get me to replace the computer but I don't want to just keep replacing stuff for no good reason. Any one have any ideas what would cause such a thing?
thanks or any help
mike

 

[lutter94]

Have you checked the timing?

 

[RichV]

The computer is the only thing that it could be.

If you truly have spark/compression/fuel. I would check injectors as well.

How do you know the problem is only 3,4,5,7?

Can you borrow a ECU? Get one from a JY? What else have you replaced? How/when did this issue start?

 

[Mike2361]

The timing is set at 10 and I forgot in the first post to say it also has new plugs, wires, cap and rotor .

 

[toyman]

This is a 100% guess. It may be possible that some of the vanes in the distributor have broken off. You might want to pull the distributor and have a look.

 

[Addermk2]

Double check your firing order. The car might have a non-ho camshaft, or you could have put the wires on incorrectly during the tune-up.

Stock firing order:
1-3-7-2-6-5-4-8

Non-ho firing order:
1-5-4-2-6-3-7-8

Counter clockwise of course.

 

[bailey_57]

my money is on firing order look at the cylinders you named as not firing, the ones that don't intersect with each other

 

[Mike2361]

Thanks for the reply's.. I have checked the firing order some where around 10 times I keep thinking the same thing, but it is correct. I bought the car running this way so i have no way of knowing when it started. I used a inferred thermometer to check the temperature of the exhaust at the header to determine which cylinders were not firing. I'm getting 400+ degrees on 1,2,6,8 and 100 on 3,4,5,7 and it runs like junk no power. As far as the the ones that don't intersect with each other I'v been chasing that idea around in my head for two weeks but cant come up with anything other then firing order, but again it is correct...

 

[RichV]

When you said it has good compression, you've done a compression or leakdown test? If you have bent valves, you should know from the results.

Without knowing the internals of the motor, or when the last time it ran right it's a tough road. But, it's gotta be fuel or spark.

Does it have any mods? Have you watched the distributor turn as you crank the motor? Turns all the way?

And last, the firing order, should be HO, cap is marked with the #1, the rest follow in a CC fashion around the cap. Have you ligned up the timing? IE crank to position, verify cam is at position, and distributor is at position? I had my distributor 180* out and it runs, probably on 4 cylinders. So maybe look at that as well.

 

[CC'S95GT]

Do you have a NOID light? It plugs into the injector connector to show whether the electric signal is getting to each injector.
Verify each each of those cold cylinders is getting spark.
It does sound like a computer issue.
Toyman has a decent guess but the dizzy doesn't have to be pulled. Just the cap and look at the steel ring under the rotor.

 

[Addermk2]

Thanks for the reply's.. I have checked the firing order some where around 10 times I keep thinking the same thing, but it is correct. I bought the car running this way so i have no way of knowing when it started. I used a inferred thermometer to check the temperature of the exhaust at the header to determine which cylinders were not firing. I'm getting 400+ degrees on 1,2,6,8 and 100 on 3,4,5,7 and it runs like junk no power. As far as the the ones that don't intersect with each other I'v been chasing that idea around in my head for two weeks but cant come up with anything other then firing order, but again it is correct...

Did you try swapping to the non-ho firing order. Your car might not have the original engine.

 

[Mike2361]

I did a compression test not a leak down. I pulled the valve covers and cranked the motor to check for full compression of valve springs they seem ok. as far as mods the only think I can see is ford racing shorty headers. firing order is set to the HO, I also set to TDC and pulled the distributor and reset to be sure. I have messed with the timing a bit i know not all motors are the same but I set it identical to my other 95 GT and adjusted it a bit from there just a degree or two until it ran nice with no backfiring or popping and put the spout plug back. I did it this way just in case the marks on the harmonic balancer are off. I'm sill thinking fuel but with all new injectors (i did check to make sure the solenoids on the injectors are working) and the same cylinders not firing I guess the computer is the next item on the list. I will try to hunt one down on ebay I guess.

edit: The non HO firing order sounds like it could be the issue it makes sense for 7 and 4 as they could be switched but 2 and 8 are in the same position on both motors but I will try that when i get home. Thanks I never would have seen that.....

 

[Mike2361]

That was it not an HO must have been a motor swap... Thanks for all your help:notworthy: you guys know your stuff! And I just ordered the computer... I'll have to see if I can cancel it..

 

[Musturd]

Glad you got it fixed , yea [MENTION=8201]Addermk2[/MENTION] knows his shit

 

[Addermk2]

I was honestly surprised that nobody else had picked up on that.

 

[RichV]

Nice call. Non HO is so 80s.


But doesn't that present an issue with fuel? Just switching the cam out forces the motor to be a non HO order, but the injectors still fire in a HO manner.