Please help with my C4 before I go insane!

[glenco]

No Bobby, just that C3 only needs Spark, Fuel & Air no computers no injection simple as an ole skool fooken tractor 

Dont worry Jethro, Ive been thinkin that for a while! Pull the motor out of my T bucket & stuff it in the corvette! It would be way faster as well matey 

[bfit]

I read a write up on a C4 with a fuel injected 540 BB a few weeks back
Make for a quick C4
Bfit

[gtc]

I'm no authority on C4s, but I do recall a tale of a C4 that was throwing weird engine codes and proving crazy difficult to diagnose. The problem ended up being a byproduct of a poor wiring job done long ago by the converter and eventually causing issues years later.

Just a thought.

[Jethro]

I had  a similar issue with my old C4 thats why I had the spare new MAF i gave to Glenn. Chased it and chase it, then took it to two locally supposedly top flight tune shops in the gong.... replaced this ..... replace that.....  better but not fixed

Eventually  bit the bullet and took it to S.R. he and he's I.T bro spent some time on it but and 

[glenco]

I'm no authority on C4s, but I do recall a tale of a C4 that was throwing weird engine codes and proving crazy difficult to diagnose. The problem ended up being a byproduct of a poor wiring job done long ago by the converter and eventually causing issues years later.

Just a thought.

It seems the possibilities for problems are endless in a c4 Anyone got a nice c3 they want to trade??

[Jethro]

Come on Glenn you have a Beaut C4 and it's hopefully not that big a fix just need to get it to someone that knows what they are talking bout....

[gtc]

It seems the possibilities for problems are endless in a c4

You can get such problems with any car that has computerised engine management. An experienced C4 mechanic should be able to sort it out.

[Ausrs]

Has the issue with this car been sorted yet ?

[Vettech]

Disc battery for a minute resets codes, the codes you have are as stated before. All centre around the MAF and the relays. The relays must be the correct part # for MAF and MAF burn off ie coil res and contact resistance. Strange your not getting a 36. It's very seldom the MAF. 33 & 34  are set in the first ~30sec (may not show on the screen for a minute or two) 33 means that on START UP when in the choke period there is too much air being draw thru the MAF whilst 34 is not enough air - check idle set up and the choke injector is ok - yes that's injector #9 (inj cleaner only runs thru it for ~8 or so secs, maybe not long enough to clean years of crap. Next issue is wiring and connectors which harden, become loose etc to the relays. The relays, connectors etc are usually pretty close to #7 manifold. Check your Batt, leads, and earths. I have had your problem for some time, I fiddle under the hood and it goes for months, then I do something else and it's back, however, I also get heat soak into my starter and restating mimics a low to flat battery, this puts low volts into the computer which brings in  33,34,36 and for good measure sometimes a 42 (EST module) so the start may have a bad "ping" but as soon as the volts comes up the module runs ok. These codes are for Start Up conditions only and should not effect warm running operation. That bloody LIGHT is just so annoying.

[glenco]

Problem not sorted yet. Thanks vettech, I have checked all the wiring to the maf relays when I changed them,I bought them from Ecklers in the u.s. so I assume they are correct relays. Also my car has had the cold start injector removed, could that still be a problem?
It would be great to be able to drive vette again, I do enjoy it when its running properly  Cherrs all 

[Vettech]

It may explain the code 33 or 34. If all else is STD can I ask why is it removed. If when cold you apply foot to peddle to get it started then this will draw more air and set a code 33. If you don't, it may detect low air and set 34. Once set they stay till a hard reset. Battery on pad is low - by for now

[Vettech]

Oh - be fore this shuts me off - even though these codes are set, they should not effect the drive ability of the car. 33/34 are only detected in first ~30 sec upon start up. 36 is the MAF burn off - the actual burn off is activated if the car is run for "X" time and then stopped. Relay supplies 12v to the hot wire and heats for "x" seconds to burn off any grim / residue stuck to the wire. This wire is hot whilst running and its temperature is related to its resistance thus more air cools it - more air needs more fuel, computer reads resistance and varies the fuel accordingly.

[Ausrs]

re reading the thread it appears that most electrical bits have been replaced,Is this a lhd or a converted rhd car ? if its a converted car maybe its time to look at some of the wiring

It may be fuel injected but it still only needs air fuel and spark to work ....just more wires than a carby car and a few more sensors.

I had a no start issue with my car that had me stumped for a while (original lhd still),pulled my hair out until I found the broken wire that didn't let current run through to injectors

I also had a new memcal made that installed a tune from an 89 model that deletes the cold start and I had the egr system programed out ...makes the electronics a little simpler 

[Vettech]

Very interesting! I'm testing my memory here, but didn't GM change to sequential injection in 88, I suppose it would not make much difference, instead of injecting all odds then all evens, it would do each individually. Give better power + econ, but by 88 they all had all Alloy Heads and roller rockers. My black book only goes to 90 and I'm now having self doubt. Umm maybe SHE is right - dementia setting in.........

[Jethro]

Come on Glenn you have a Beaut C4 and it's hopefully not that big a fix just need to get it to someone that knows what they are talking bout....

Come on Glenn bite the bullet son ! Ring Steve at S.R.Perforance....

[bfit]

Buying  C3 would be a good alternative.
Bfit

[Ausrs]

any updates ?