iroc wont start sometimes

Had the car a few months now here is a list of things replaced. ECM(twice),ign control mod,mass sensor, tps, iac,full tune up, pic up in distributor,cylinder and key for vats,Car starts good most of time and then it wont have to use starter fluid. Im getting a weak light from the noid when i check the harness. I am lost took to dealer they said put another ecm in so i did still have same problem. The mech I use sometimes(Calvin Nabors) says the problem is not cosher. There are no codes, have spark, and compression, have good fuel pressur(47psi) Injectors ohm out around 18.What the weufgw is going on. Thanks Tony

Waht exactly is (not) doing? Details??

yea... you havent really told us anything. what doesn't it do? when doesn't it do it?

when it won't start... does the starter not crank? does the fuel pump not make pressure? do the lights not come on???? you gotta be a lot more detailed.

Might be a spot on your starter, that's it if turns over or it doesn't sometimes.

It may be your fuel delivery, can you hear your pump coming on in the back?

alright boys thanks for replying, I'll make it easy.... the fuel injectors dont fire or receive a weak signal sometimes, starter fuel pressure and supply are good, yes ive tested the motor always turns over but the injectors dont fire. Does not matter if car is cold hot been sittin or just turned it off. Ive been trying to figure out the flow of signal I know the ecm ssays fire but what tells ecm. If it wont start i spray starter fluid the motor starts and the injectors start fireing. Pardon my spelling Thanks again,

Ive been trying to figure out the flow of signal I know the ecm ssays fire but what tells ecm.

The ecm receives a reference signal from the pick up coil which is transmittted to it via the igniton module.

Okay so I did the pick up and the module, Should I just try the whole distributor, Ill check the wires,There is one plug on the back of the dist that is questionable. but were in pretty dmn deep.Ive heard the distributors have problems. Has any one else?Like I stated in the first post it starts most of the time. Thanks again wz28 you helped me out when I first bought it too.

, Ill check the wires,.........Ive heard the distributors have problems. Has any one else?.

Definately check the wiring out, there is a weather pack connector with 2 wires going into the distributer cap, those are the feeds from the p/up to the ICM, they tend to get heat baked and birttle, then break very easily when you're not paying attention (setting timing, whatnot).

As for the distributers, I don't believe, or have heard that the remote coil ones like you have are as prone to problems like mine, I have the coil in cap one, and yes, I just bought one sitting in a box awaiting install because the shaft bushing is dead.

The ingition parts you installed, please say they are delco. And you put the heat dissapation grease on the ICM?

a last thought after re-reading your post, did you change the fuel filter?

yes sir, delco parts, and lubed, new fuel filter and pump, One thing I have not mentioned was the second computer I installed it seem to start better but within a month its back to starting 75% of the time.

Hmmm, for the giggles of it, on the wiring harness for the injectors. Theres a big, hard to miss connector, that utilizes a locking tab to keep it snuggly together, I wonder if the tab is missing and harness isn't fully contacting each end together?

I'm only fishing at this based on the weak noid light indication. When the engine starts normally, the light is "normal"?

well its gonna let me fix it:grinyes: The wife gave up on her iroc and is driving the grand wagoneer to work now and on top of that it wont start without ether at all now. It tries but no good. I did check the pressur again and its 45 but after you turn the car off it leaks down in 30 mins. Would this be the problem:uhoh: Ill put new injectors in it for $300 or so if the car will start all the time.On top of that I recently replaced the pressure line and steering pump in my mom in laws buick and it keeps blowing the oring every couple days! What am i doing wrong.:banghead:

The pressure bleeding off is normal.

So now it won't start at all even with ether? You have spark?

It's gotta be an electrical malfunction some where down the line. i know you said you replaced aprts of the VATS system, but you may want to look into bypassing it, at least temporarily, to eliminate it from the picture.

Oh, and which o-ring, what year Buick? Post it up in the Buick forum.

forget the 92 lesaber, rack pinion restricted, the iroc would only start with the ether yesterday, today started the 3rd try and started everytime since.the vats is good i think the security light goes out when i try to start it and dont it lock out the starter too? This harness you mentuioned is thet on tune port inj cause I dont see it yet the wires come twisted in two pairs out of the rt fender and go down behind the block where they come up as 4 pairs for each side. hope you can follow that Its hard for me to explain. Hang in there with me Im were gonna figure this out , do you have a gm shop man I found one for 89 camaros its 2200 pages for $80 im gonna buy and see if it can help.thanks tony

Ok, but the 2 harnesses should come together in one main marness somewhere before the ECM. But if the nodi light is dim whn the problem occurs, then there has to be some sort of added resistance somewhere in the circuit and not enought amperage is getting to the injectors to fire em off correctly.

Im with ya, tried lookin yesterday, they seem to disapear once they go into the front rt 1/4 panel as I dont see em again under the dash, anyway I will look closely and get back with you. Its very hard to disect the harness behind the block, but you know what they say, thanks once again

I was just sorting thru some older post and some of the conversations with malletswinger,wright, and quicksilver, well you guys are funny.Im stuck at wotrk right now but hopefully tommorow ill find this wiring harness connector and all will be well

Cant seem to find any loose connections yet , Had a front wheel bearing go bad at least I was able to fix that prob. Does any one know if a quirky starter solenoid would cause the ecm not to get a start signal for enrichment and cancle diagnostic?:screwy:

just curious..you said when you installed a new ecm it ran better for awhile .Did you re-use the same PROM or make sure its the correct one for your vehicle ,could possible be an updated one available.Check the dealer if you havent done this.Take the number off the PROM and the VIN and call the parts dept.If you already done this then ..back in the wiring you go.