Injector issue with 1990?

[cp1joel]

hmm after speaking to the original mechanic this morning, he believes the cams were too big for the car. The car was intended to be for racing rather than street. He made a suggestion to put the original cams back on and original chip. According to him the car ran beautifully and was much more pleasant to drive in its stock form. What are your thoughts on this? If it was up to me I would have kept the car stock to begin with.

[jss06c6]

Trying to troubleshoot without being there or getting codes to assist with guidance is not very fruitful. As a personal comment, I find it very hard to believe that Marc could not hit a 95% tune on your car IF he knew exactly what had been modified AND that you have no other issues, either mechanically or electronically with the car. If you told him what the cam specs were, I'm confident he could hit the tune, or told you the cam specs were incorrect for the LT-5. More likely, you have something else going on, or the cams were not installed properly to begin with (inaccurate timing).. My $.02..

[BlackSheepz]

Just read through the thread.
I'd personally stand by Marc Haibeck's chip but that's just me. He's a magical space ninja, I don't think there is anyone that knows more about these engines than him.

I Was also having problems with my car a few weeks ago. Car ran well, but also had a hesitation on hard acceleration. I'd floor it and it would accelerate adn then at about 4000RPMs it would feel like I floored it again! Big burst of acceleration. I always thought I had a vacuum leak, but then I started getting the shudder and sound like you describe.
Marc Suggested it was the injectors and that the flywheel was compensation (as you have suggested foryour car).

I replaced my injectors (First and only plenum pull and it was solo, yikes!). Car started and ran beautifully after that but the hesitation was still there. Marc suggested the 02 Sensors. Got hte new O2 sensors from Jerry and replaced them when I put a Corsa Exhaust on the car last week actually. When I first started and ran the car it was AMAZING. Then when the car warmed up I floored it to accelerate and holy sh*t things were NOT ok. The thing shuttered, started to go, bogged down, started, bogged and that was it. Car went into check engine light territory and just did not run well.

Next step was to replace the fuel pumps. This was the solution for my car. When I pulled the pumps one of the hoses was very badly cracked and the fuel strainers crumbled in my hands. I replaced both pumps, and the hoses and now the car runs better than It's ever run in my ownership.

To make a long story even longer, have you checked your Fuel pumps?

If Marc made you a chip, and he didn't freak out when you told him the specs of your cams and mods, then I'm guessing it's not the ECM or the cams that are the problem.

[cp1joel]

Hey all,

I totally stand by Marc's chip as well and believe he tuned the car as to what I supplied him.

Correct me if I am wrong, but the tuning on his chip eliminates any tuning done to the original calibration package (blue cover)? So this means that the car would be only reading his tune right?

Spoke to the mechanic this morning, has he said the car dyno'd about 380hp at the wheels. That is roughly 100 less than the dyno done a couple of years ago.

He still think the tune is totally wrong and that is what is causing the car to be super lean under 3000 and super rich above 3000. He doesn't believe it is anything else (that I have suggested).

As you can imagine I am stuck between two places, but I will bring the car home and investigate further.

So it will be injectors, spark plugs, coils, MAP sensor hose and fuel pumps as possible culprits.

Cheers guys

[jss06c6]

What is your tuner using to measure fuel trim in the VE tables? What BLM numbers is he seeing? Has he looked at the PE table to see what it's commanding? There are two VE tables and two spark advance tables, one set for "port throttle closed" and one set for "port throttle open" (secondaries closed and open). I'd be interested in knowing what your tuner is seeing as "super lean" and "super rich".

Sent from my XT1585 using ZR-1 Net Registry mobile app

[Ccmano]

Is this the same guy that said the cams were too big? If so I think it's time for a new mechanic/tuner. The problem I see quite a bit these days is that today's technicians don't understand or can't fully read these old obd1 memcal systems. I'd be curious to know what software he is using.

I suggest you get yourself the proper software (TunercatRT which is free) and cable to connect to the Odb1 port under the dash.

http://www.moates.net/aldu1-and-cabl....html?cPath=64

Load the software on a laptop and do some datalogging. Datalogging is simply driving the car and letting the software record what the system is doing. 10 minutes of driving with a few full throttle runs is all that is needed. The data file can then be sent to Marc for analysis.

This will help Marc understand if there is a mechanical/sensor issue or if the tune is correct.

Good luck
Hans

[jss06c6]

Originally Posted by Ccmano

Is this the same guy that said the cams were too big? If so I think it's time for a new mechanic/tuner. The problem I see quite a bit these days is that today's technicians don't understand or can't fully read these old obd1 memcal systems. I'd be curious to know what software he is using.

I suggest you get yourself the proper software (TunercatRT which is free) and cable to connect to the Odb1 port under the dash.

http://www.moates.net/aldu1-and-cabl....html?cPath=64

Load the software on a laptop and do some datalogging. Datalogging is simply driving the car and letting the software record what the system is doing. 10 minutes of driving with a few full throttle runs is all that is needed. The data file can then be sent to Marc for analysis.

This will help Marc understand if there is a mechanical/sensor issue or if the tune is correct.

Good luck
Hans

Exactly!!

Sent from my XT1585 using ZR-1 Net Registry mobile app

[cp1joel]

Hi all,

thanks for the suggestions so far, will look into data logging.

A bit of an update on the ZR1.

Received the car back from the mechanic, they looked over the entire thing.

Checked injectors, spark plugs, fuel pressure, compression, o2 sensors etc and are still adamant that the issue likes with the tune.

What is interesting is that Marc tuned the car for stage 1 cams.

I have been told by a couple of people that the cams were reground at a much more radical profile. I wonder if this could be causing the issues I am having? I may have provided him the wrong details.

I have print outs with the cam spec and believe they are up to date but I have a feeling they are not Stage 1.

Is anybody able to look at these print outs?

Thank you all

[5ABI VT]

Originally Posted by cp1joel

Hi all,

thanks for the suggestions so far, will look into data logging.

A bit of an update on the ZR1.

Received the car back from the mechanic, they looked over the entire thing.

Checked injectors, spark plugs, fuel pressure, compression, o2 sensors etc and are still adamant that the issue likes with the tune.

What is interesting is that Marc tuned the car for stage 1 cams.

I have been told by a couple of people that the cams were reground at a much more radical profile. I wonder if this could be causing the issues I am having? I may have provided him the wrong details.

I have print outs with the cam spec and believe they are up to date but I have a feeling they are not Stage 1.

Is anybody able to look at these print outs?

Thank you all

I would imagine you did send the specs to Marc to see what he thinks ? He usually replies very fast.

[cp1joel]

Yer this is what I sent him for the tune.

He mentioned that they were US Stage 1 cams.

So maybe the tune is correct after all?

They were purchased as Stage 1 cams and reground here in Australia.