ok heres the deal, Im working on my buddies 96 z for him, we did a hotcam, springs, rockers, and a stall. Ran great for about a week, then after he put the stall in which was after the cam it started sputtering and died out, and would not start again after that. Since, I have put in a brand new MSD opti thinking that was his problem because he did have a coolant leak. Go to start it and nothing, just cranks away. I checked for spark at coil, and the plugs and it is good. Fuel pressure is right at 42psi with COEO. I am stumped as too what this may be, I tried putting a screwdriver on the injectors to see if they are clicking, but could not hear anything, like they are not pulseing. Also ecm was tuned by madz28. One thing I have noticed is it will want to start more when the pedal is too the floor, and sometimes will start but sputter and not stay running on its own. need some imput guys...please help.

 

did you pull a spark plug and see if you have spark?

 

yea has spark at plugs, its a brand new opti. I took it out of the box and bolted it on. I thought the problems we were having may have been opti related but now I think it has to be something else. I cant hear the injectors firing.

 

Have you scanned it for codes?

 

Id check the injectors with some noid lights to make sure they are pulsing (you can also squirt some fuel in the air intake of the intake manifold and see if it starts - if it does you have fuel problem). If you have spark and fuel at the cylinders, next to check cylinder compression. If you have spark, fuel, and compression, then next is timing (opti, wires in wrong order, etc).

 

ok well it will start but does not run right at all. wont idle on its own and pours black smoke, but why so rich. Im confused as to what is wrong and what to check. all opti wires are right, has spark, and fuel. It threw a mass air code p0100 but i tried another mass air and nothing changed. Any help would be awsome guys, thanks

 

Check the coolant temp sensor in the water pump. If that wire it off or the sensor is broken, it will read "cold" and the PCM will pour extra fuel in for a cold start.

Since it started after the converter install, check the O2 sensor wiring. If you nicked a wire or crushed the wiring harness for the O2's it could make it run rich.

Have you checked the power supply to the MAF sensor? Key on, you should have 12 volts, measured between the pink wire in the MAF harness connector and the black/white ground wire. There are other loads on the same fuse as the MAF sensor, as well.

Does it start easier if you hold the accel pedal on the floor when you crank it, to put it in "clear flood" mode?

Have you checked the injectors for major leaks? Pull the rails up and pressure the fuel system.

When you did the scan, is P0100 the only code you found?

 

yes, that was the only code, it starts better when the pedal is floored, wont want to start if your not pushing the pedal. Im going to try and get a volt tester and check the maf pigtail, all fuses were fine. the waterpump is not on right now, we left it off after the opti install to make sure it started but it didnt, so the front of the motor is not assembled yet. Would that coolant sensor cause the issues along with the p0100. The car wont run for very long, and just runs terrible. Everything is fine as far as ignition and fuel go, but im not sure how to go about fixing the maf problem.

 

Is the coolant temp sensor still plugged in and hangin there? If so, its reading air temperature, and not coolant temp, so its going to prevent the PCM from going into closed loop, and its going to cause elevated idle and excessively rich mixture.

If the sensor is not plugged into the harness, you should be getting a code for it.

The 97's have a problem with the pink MAF wire breaking somewhere in the harness. I haven't heard of that being as much of a problem with the 96's, but its possible that is why you are getting the MAF code. Measuring the voltage on the wire will tell you if that is the problem.

 

ill try and get something to test the volts on it, the coolant sensor is not plugged in, but no code. Im thinking this is the problem it wont run at all.

 

Shot out in the blue but...


Did you un hook the battery when you did that? Sometimes if you touch the body of the car with lets say the starter and it sparks...it fries sumthin expensive, probobly the PCM.

Just my 2 cents, prob not..but maybe

 

u say it starts better with the pedal floored.

When my opti took a crap I had to do that.....hmmm maybe bad opti

 

brand new opti--0 miles on it. im thinking a maf problem

 

I put a brand new opti in also. It was defective from the manufactuer. Theres always that chance. But obviously check the "less headache" parts first.

 

it just does not seem like a opti problem, its getting spark and its a brand new msd unit.