i have an 89 iroc z with 5.7, 700r4, with tpi and i have this problem that the engine will crank but the fuel pump does not energize or there is no pulse on the injectors. i replaced the in tank fuel pump, wiring, relay, injectors, pressure regulator, and now a new ecm. still the same problem. could the vats module be bad. where and what is it. i have run out of money and patience. i hate this vats system. i would like to remove the system completely or reprogram the prom to eliminate this input/outputs.

I have the same dam thing help!!!

First, you have got to learn how to do some electronic troubleshooting. Changing parts until you fix the problem just leads to frustration and a low bank account balance.

Start with the fuel pump relay. You should have system voltage on the thick orange wire at all times (12+v). You should have a good ground at the black wire with a white trace (check continuity to ground and/or use this as a ground and check voltage to the battery or another known 12v source). The dark green wire is the trigger wire, this one is a little trickier to test. Set up your voltmeter with one probe touching the contact for the dark green wire and the other on a good ground (you can use the black wire with a white trace if it checked out as a good ground). Position the voltmeter so you can read it from inside the car. Click the key into the on position and check the reading. You should get 12+v for about two seconds and then it will taper down to zero. This is the ECM priming the fuel system, it will not trigger the relay on all the time until the engine starts running. If you have 12+v for two seconds on the dark green wire test the tan wire with a white trace in the same manner. You should get 12+v on the tan wire for two seconds when you cycle the key. If all of this checks out your relay is good and you just saved yourself $15 for a part you didn't need.

If some part of the relay test doesn't pass trace the wiring back to it's source and correct the problem. If the dark green wire (trigger) doesn't get voltage check the appropriate pin at the ECM and see if you get voltage when cycling the key as noted above. If not then there is a problem in the ECM. Make sure the ECM is getting power and has a good ground before deciding that the ECM is the culprit.

If the realy tests out okay then test for power at the fuel pump plug. You will need a friend to help you as you will have to be under the car with the voltmeter. You should get 12+v on the tan wire at the fuel pump for two seconds when cylcing the key. If you don't there is a problem between the relay and the pump. Trace the wire and correct the problem. Also, check the ground for the pump.

Always troubleshoot an electrical problem before dropping your hard earned cash on new parts. That way you fix what's broken instead of ruling out every possibility with a new part. A lot of problems on these cars are caused by corroded terminals, shorts, and damaged wiring. The newest third gen is now 17 years old. A lot can happen to wiring in that time.

if you had a problem with your vats system then your car wouldn't crank. the vats system will disable the starter, fuel pump, injectors, and the ignition. i have had my share of problems with my vats. have you checked for spark? your ignition module also send a singal to your EMC to turn on your fuel pump. like TKO said there is a lot of trouble shooting that has to be done before you start replacing parts. i had a bad injector that grounded the circuit and backfeed to the ECM. in my case this is why i had no fuel pump or injector pulse. my ECM thought my injectors where on even before the car started so it wouldn't pulse the injectors = wouldn't turn on the fuel pump. give us some more diag info to work with.

thanks tko. by the way i have visited newark often and had lunch at the steak/beer pub on main street when i was deployed to dover afb in 2002. i checked the fuel pump by putting power on terminal g and a hot source. the pump runs. what i did not check was the dark green wire and the tan, the orange was hot and black white was a good ground. the ecm ground, i don't know about, do i ground the box or is there a ground wire to check.

the engine has spark because it backfires when i prime the system with starting fluid. the injector connector and bad ground could be it. one was damaged during engine install. the noid lites test failed on all injectors. by the way have either one of you modified the prom on the ecm to eliminate emissions, vats, or other inputs. a local outfit, fuel injection specialties here in san antonio said they could mod mine to eliminate all these systems. what's your advice on this subject. the reason i asked is because the previous owner ripped out all the emissions junk out of the engine and texas has no smog checks. i can't afford to replace all this stuff now. thanks for your help.

has the car been sitting for a long time? when i had the my bad injector the noid light also failed on all injectors. even now with everything working the way it should the system will not light the noid light bright enought to see it in the day light. i would run the test again with every injector unpluged it the same time. if more then one is backfeeding and you have it pluged in it can cause the ECM to not send a singal. as far as the emissions go i would say go for it. i'm not sure what the guy in your area will charge you. TPIPARTS.net will do a piggie back that will turn all that off for cheap money. i don't not have any of that turned off in my Eprom because i'm still running all my smog CRAP without cats.

can you get the car to run at all?

the test that tko suggested failed, none of the hot wires had voltage on the fuel pump relay. i will disconnect all the injector connectors and test one by one. i bought a haynes manual today and now i have electrical diagrams to go by. the engine started and ran a month ago but it ran poor and backfired, the engine had a bad cam and lifters. the previous owner adjusted the valves way past zero lash. so i overhauled the engine and now its o.k. the car sat for years before i bought it. that's why i had the fuel tank cleaned, installed new in tank fuel pump, and bought new accel injectors which are 24 lb and are probably too big without programing the prom for new info. the wiring was a nightmare but i repaired everything i could. but now the fuel pump does not energize unless i hot wire pin g to a hot source. but the injectors don't pulse. can the vats module be bad. i intend to check voltage from the dark blue wire to the ecm. i let you know what happens. thanks for your help. i'm so frustrated i'm thinking of getting rid of tpi and going carburetor but not just yet.

i got pules to a spare injector that i can hold and it pules but not in the fule rail what the hell is going on i think ice and yes fule pump works was thinking of i'm thinking of getting rid of tpi and going carburetor but not just yet going nuts help.

the 24lbs injectors work just fine with the stock tune. it sounds more like you might have a wiring problem. i guess the vats could be bad but it would cut the power the starter also. when you turn your key on does the security light stay on or will it go out after a few seconds? i'm sure you checked before you posted but is the power for the ecm at the battery is pluged in?


tmck40. does your car run at all?

yes my cars run on starting fliud but thats it and security light gose out ecm is getting power iam going to shot the dam car with amy 12 gaug

this is what was happening to my car. the only way i could get it to start was with starting fluid. it would run after but not very well and only for a few minutes at most. when you get it started unplug your injectors one at a time. unplug and plug them back in as you go. this should change the way the car will run. if you unplug a good one then the car should run worse. if you unplug a bad one then it should either run better or it shouldn't change at all. or you can always ohm out the injectors. they should be 14.4 ohms i belive give or take a little but not much at all. you have to remember the injectors are wearable parts. if the car sits for a long time with older injectors in it the fuel will eat the coating on the injector drivers and they will stick open or closed.

The fuel pump works because you said you can get it to run by hotwiring it, so that part is elminated. The problem is obviously with the wiring to the relay. Are you getting 12v at the thick orange wire all the time (even with the key off)? If not there is a fuse holder on the right inner fender that holds a fuse for that circuit. It can blow and cause you to go nuts. I don't know why they didn't incorporate this fuse into the fuse box. If you have no power at this wire nothing else will mater, as that is the current that the relay is switching to turn on the pump.

i am not getting 12 volts on the orange wire or any wire on the fuel pump relay. i don't see that fuse connector you are talking about. what color wire is it.

The fuse holder is an inline holder that is black (the case is secured to the body and the fuse, in a holder, snaps into the case). The fuse is on the right inner fender near the coolant overflow bottle. The wires going into it should be orange, maybe with a white trace depending on the year. It should be a 20 amp fuse.

thanks, i see that the previous owner cut that fuse holder out and soldered the wires direct. the wire is hot but of course there is no protection for the circuit. i will splice a fuse into the line. my question is that i thought that this module was my vats module and it turned out to be the cruise control module and it is located on the pass side near the ecm. do you know where the vats should be. a local speed shop told me that vats is inside the ecm. is that true. he said he could program my chip not to have vats. at this point, i might as well troubleshoot the fuel pump orange wire for a short or open since that is one problem.

So has anyone suggested the Oil Pressure Sender??? If that thing goes out or comes unplugged, no signal will get to the fuel pump, as a safety feature: If the engine has no oil in it, it will shut itself down to save the internals..

don't know if i'm comparing apples to oranges but on my 89 firebird there is a hot wire coming right off of the battery positive cable. It feeds the ecm and provides the power for the fuel pump. This wire had a bad fusible link ( link is about 12 inches away from terminal of pos. batt. cable). caused same exact problem. another symptom of it was the check engine light would not light up when the key was turned on. Hope this helps.

i got so pisd off at the tpi i wint carb i it runs sweet and it is staying carb f@$k tpi go old school.

That is wrong.
The oil pressure sender is for the gauge.
The oil pressure switch is a backup for the relay in the event the relay fails.

she has a rod knock so out come 350 in go's my dz 302 i build in 06 and she runs tits .

o.k. it is fixed. i found the red wire that was the ecm power. i connected it to a factory splice of four into four wires near the driver side firewall where all the tpi relays are. the fuel pump turned on, injectors primed, and engine started and idled but real bad. the prom is going to have to be burned to eliminate all the pollution stuff since the previous owner removed everything to include the a/c. he tried to turn this car into a 1LE option iroc. thanks to everyone for your help. i really appreciate it.

Reviving the thread a bit as I am having the same exact problem and have a question. Where is the terminal "G" that you can apply power to to start the fuel pump? I have the factory repair manuel and the chilton and hayes book and still can't figure out what this is.

I'm going to follow the other steps suggested in here, at least the ones I haven't allready tried.

My 87 Trans Am won't even try to run without a spray of starter fluid into the intake, the fuel pump isn't coming on for sure. I had the fuel filter off and tried cranking it, no fuel came out of the line.

I'm also curious about the fuse for the fuel pump, is that the fuse located just above the battery? I haven't seen any others along the fenders...