I recently bought a 92 camaro w/TPI. It had a 305 in it and it was knocking real bad. I swapped in a brand new 350. The 350 is stock and made for that year of car. I bought new 21 lb injectors and a 350 Prom chip direct from GM store. It runs pretty bad after the swap. I measured fuel pressure at 34psi at idle with the regulator hooked up. With regulator unhooked it reads 45 lbs. I left gauge hooked up and test drove the car. Fuel pressure remained strong. I changed the fuel pump and fuel filter anyway. Didnt help! I'm gettin good fire and no check engine light. I have base timing set at 8 degrees BTDC. The computer is advancing the timing correctly. The only thing strange about everything is that the tachometer reads incorrectly. It shows like 6 grand when the car isnt even pulling 3 grand. Could I have an ignition module crapping out on me? Does it matter if the fuel injector connectors are on the right injector as long as its on the same bank? Please help!!

 

Sounds like an ignition problem with the tach. I would think that the injector cables would matter. When you say it runs "pretty bad", what is it doing?

 

Did you install a 350 knock sensor? You need to.

 

when i replaced my ignition module it fixed the bad running and the tach problems.

 

I did install a 350 knock sensor. That took care of the code 43 that previously popped up. I'll probably try the new ignition module. By running bad, i mean, the thing runs like a weak 305. Its shakey on take of and acts like its out of time although its right on the money on timing. I appreciate your help guys.

 

well, I put a new ignition module in and still no luck. I just believe that the tach reading that far off points to something in the ignition system. I'm wondering if i have a possible pickup coil problem. I would think this would cause it not to run at all though. I did check for proper powers and grounds to the back of the instrument cluster and I have them. Any help or suggestions would be appreciated. Thanks

 

Let's not guess when offering up advice. No, it doesn't matter which injector is plugged into where, as long as it's on the right bank. All injectors fire at the same time on each bank.

Did you use the distributor from the 305? When the tach goes funny the first thing I'd look at is the pickupcoil/distributor.

Are you sure you got the correct chip? Throw the 305 chip in there and see if it runs better...

 

It ran the same with the 305 chip as it does now. The distributor im using is out of the 305. I do have another spare 305 distributor and pickup coil. Would you try to swap them? Thanks

 

Hmmm... that fuel pressure doesn't sound right. The 45 at idle with the guage disconnected sounds okay - provided you plugged the vacuum line so there wasn't a vacuum leak while you took that 45PSI reading. The 34PSI with it disconnected sounds REAL low. I've never heard of one dropping off that far. Should be pretty close to 43 at idle and increase as vacuum/load increases. I'm wondering if you didn't plug the regulator's vac line going back to the intake while doing the disconnected reading, which would cause a vacuum leak and throw everything off.....

What PSI were you reading while driving around? You said it "stayed strong", but it should have been 40+ the entire time. The way the regulator works is it INCREASES fuel pressure during acceleration and higher engine loads. If it started out at 34 and never made it above 40 the injectors are not firing right and you'll never get the correct performance out of the engine.

Hope this helps a little bit. Have a Great Day!!!


- Vern

 

"Guessing" is all you can do without having the car right in front of you and hooked to a full engine diagnostic setup.

305 distributor is the same as the one used on the 350. If it was working good with the 305 then there really is no reason to suspect it is at fault.
Make sure you didn't crack the cap though, and put it on securely.

The tach "going funny" isn't conclusive of anything except maybe a bad tach. The tach's in the 3rd gens were never known for longevity or accuracy.

Stock fuel pressure with all lines hooked up should be around 36 psi at idle and will vary with barometric pressure. The pressure will also increase a little as you open the throttle, but not a lot, (a few psi).

Timing at 8* is incorrect, should be 6*. Some people have gotten away with going to as much as 10* and said they had no problems. I myself have never had mine run well with it set to anything other than 6*.

You need to hook a scanner to it and see what exactly the engine is doing and what the ECM is seeing.

 

Thanks guys. Im a dodge technician and have the knowledge of how things work but have no scanner that will work on this vehicle. I do have connections at a chev. dealership. Im gonna see if I can hook it up over there.
Also, I borrowed a service manual for my vehicle and it says fuel pressure should be 40.5 psi at idle and like above 45 at 0 vacuum. Mine is 34 at idle. I may have a bad regulator. I guess i'll keep fighting it until i win . Thanks for your help.