I dont think i can take this any more. Heres what it does

Car turns on only when i pump the gas pedal, must keep it at 1500 or more for it to run. I can only get it to rev to 2500 rpm, sounds like a washing machine and it has no throttle response or power.

This is what ive done to try and fix it.

-Rebuilt engine
-repaired wiring harness
-new egr valve
-cleaned and flow tested injectors by lingenfelter
-cleaned out iac
-new o2 sensor
-new plug wires
-new distributor
-new cap and rotor
-i replaced all vacuum lines and they are all in the correct locations
-i sprayed all the runners and manifold and plenum connection points with tb cleaner and there is no change in idle or sound of engine, so i have no vacuum leaks.
-checked charcoal canister, no fuel in it
- just pulled the easy to get to plugs tonight, they were fouled

could fouled plugs cause all this? im lost what should i do

 

please help i will be forever grateful

 

do you have any codes in your ecm?

 

maby your catalyst is pluged

 

Off hand I would check the fuel pump (sound like its gone south)

 

I'd say fuel pump/filter too. Or maybe fuel pump regulator? -89IRO

 

thanks,

new cat

im afraid to run it long enough for it to get codes

ill replace the fuel filter soon good idea,
i checked the regulator holds pressure at 43
and i tested the pump its good too.

 

If your plugs are fouled, you need to start with a fresh set at the standard gap. Don't bother with any of the designer plugs, just plain old ACs or Champions.

While you're in there, test the continuity of each of the plug wires. Just because they are new doesn't mean you couldn't have a bad one(s). Test the ignition coil resistance (primanry and secondary) while your at it.

Since your fuel pressure is right on spec, and the injectors were serviced, chances are that you have a faulty ignition or other contamination that is preventing combustion.

You should also test/set the TPS voltage. I didn't see that mentioned in your list. And just for argument's sake, remove the FPR pilot vacuum hose to see if any fuel is relieving through the regulator diaphragm.

Incidentally, there is no need to run the engine to retrieve error codes. You want to have the engine off for that.

Also, "pumping" the accelerator on an EFI engine does nothing for startup, unless you are holding it to the floor (over 80% TPS). Doing that will invoke the "Clear Flood" mode and stops all injector pulses to help start a flooded engine.

Just a few more questions:
Do you have an aftermarket PROM?
Stock injectors or aftermarkets/upsized?
Gutted MAF?
Are you using a breather cap for the oil filler?
Did you clean the cold start injector while the other eight were being serviced?

 

do as metioned above. i'd suspect a ignition problem. ie look at the distributor. pickup coil, module, ign coil.

 

today i am changing fuel filter and changing spark plugs

ill also check plug wire continuity and coil resistence as you mentioned

sry left it out, i did check tps sensor voltage its at .54.

stock maf, stock injectors, stock chip, not a breather cap, and i sprayed the **** out of the cold start injector with tb cleaner.

didn't know that about the pumping, cool

thanks ill post what happens after i do this stuff.

 

New plugs, new coil, new fuel filter, and the wires are fine.

It started and ran for 1 second then died.

Now it wont start anymore.

Im willing to try one more thing before i take it to a dealer and pay too much for something thats probably just a stupid mistake.

I also checked the codes and there are none. (well code 12, obviously)

 

I don't know man, it still sounds like a fuel/ignition problem. Did you say you checked the fuel pump itself? What did you do to the car right before you started having problems with it? Once you get this all figured out, you'll be happy with yourself, so keep fighting at it! You'll get it. -89IRO

 

i bought the car for 1500 bucks. its never been running at all. THe previous engine had water in the oil so i didn't even try to run it with that. but that wasn't the original block, so i made the guy i bought it from give me the original block. I had a machine shop rebuild the short block and some corvette aluminum cylinder heads. its got roller rockers too. THen i put it all togethor and it actually started right up but still ran like crap. found out i had a vacuum leak, fixed it, still ran like crap, then i did all the stuff i did in the first post, including what i did today, and now it wont even start.

 

I see...

 

Check your timing...

 

timing is set at 6 degrees

im gonna use the tpi swappers guide diagnistic charts for not starting and see what i come up with.

thanks everybody for helpin out.

 

It would be very good to verify the correct fuel pressure at the Schrader fitting.

 

well look at it this way, once you figure this problem out your gonna have a very sweet engine with all that work you've done to it to try and fix this one problem

 

I would say timing too.
Who installed the timing chain & the dist ?
before removing the timing chain cover... play with the dist timing while a buddy is cranking the engine.

 

Vader,

I just checked pressure again today, 44 lbs. and holding. I have to go to my sister's dance recital (baah) so i can't work on the car till tomorrow. Ill keep you guys updated, thanks so much for your interest.

 

Using the tpi swappers guide diagnistic charts for a no start condition, i have narrowed the problem down to either the injectors or the ecm.

I checked for spark at each plug wire while cranking, all fine.

I used a test light at one of the injector connectors to see if i get a blinking light while cranking. It was a steady light. So now the book says to check the resistance across each injector. In the process of that now...

If the injectors are fine its the ecm. If the injectors are bad, i need to replace the ecm and the bad injectors. Ill keep everyone posted.

Thanks.

 

all my main injectors have a resistance of 16 ohms.

BUT

my cold start injector reads 3.8 ohms. Is it supposed to read this much cuz its a cold start injector? or is it bad?

 

I'm not sure about the coil of the cold start, but the service injectos seem normal. The CS only operates for a few seconds, aznd the engine should start without it after a little cranking.

If you're getting a constant injector circuit firing, either the driver transisistor in the ECM is shorted or the wire harness is grounded.

Now you're getting somewhere!

 

Thanks.

How should I check for the harness being grounded? Visually? Or is there some special test? If the harness and injector driver circuit is ok I'm gonna have to replace the ecm.

 

Like mentioned, it seems something is shorted or grounding out. Buying a GM Service manual ( Helms ) for your year / model 3rd gen will help out GREATLY, as it has a wiring diagram, troublehshooting charts etc...it's the book the dealer tech's used until everything went onto CD's.

Also...I've seen some WEIRD problem simply from grounds that weren't doing their job.

Should be a ground up near the passenger cylinder head coming from the battery area, and there should be a couple of grounds running to the BACK of each cylinder head...they are a bitch to get to, but with a wrench and some patience, it can be done without too much cussing.


HTH and good luck.

 

Thanks, I'm pretty sure I have everything grounded, I'll check cuz who knows though. I can't do it till im out of school today, ill update with info later.