have fuel pressure, injectors not working

[kre8ive_kustomz]

what would cause the puel injectors not to pulse? my check engine light came on about 3 months ago and all was good untill i disconnected the ecu, now it wont fire at all, i have pressure at the rail but nothing from the injectors..... i replaced the ecu, wasnt that, my manual says that "the ecu uses the cmp to determine the position of the #1 piston during its power stroke, this signal is used to calculate fuel injection mode of operation.... if cam signal is lost while the engine is running the injection system will shift to a calculated injection mode based on the last injection pulse and the engine will continue to run"..... i assume that disconnecting the ecu lost the stored memory setting IF this is the problem, i dont really know anything about this so i was wondering if anyone has had similar problems or heard of this problem before. also, this car has both a cam and crank sensor, but isnt this problem less likely to be crank sensor i had one go bad once and the truck didnt get spark, got fuel. any help appreciated.....

 

[BrokenTsi]

hmm. I think its the crank angle sensor.

 

[luv2rallye]

Injector pulses are timed from the cam angle sensor but the crank angle sensor must also be operating. The MFI relay and MFI fusable link (sometimes called MPI or engine) must also be operating.

 

[kre8ive_kustomz]

wow, one thing after another here...... i replaced the cam sensor and figured while i was at it incase the crank sensor was the problem i would replace that one too, anyway..... replaced the cam sensor and took the lower timing belt cover off, i noticed all these teeth from a belt so i said to myself thank god i caught it before it broke, thinking it was timing belt teeth, here the balance shaft belt had snapped. the car ran fine when i shut it off last, it must have snapped while trying to start it. will trying to start it have messed anything up, my book calls it a #2 crank belt, is this one as major as the big one? thanks all

 

[BrokenTsi]

my bshaft belt stripped out all the time. It was like that for 2 years, every time I replaced it, it must have broken the same day. Turned out the bshaft sprocket broke because the bshaft bearing went bad and it fubr'd up my whole motor. It actually still ran, just shitty oil pressure.

 

[luv2rallye]

will trying to start it have messed anything up, my book calls it a #2 crank belt, is this one as major as the big one? thanks all

No you didn't hurt anything but you were lucky. The "B" belt, as it is normally called, just runs the front balance shaft which only smooths out engine vibrations (the oil pump is on the rear balance shaft). When it goes it usually gets wrapped up in the timing belt (TB) and so takes the TB and 4-8 valves out with it. So count your blessings, you were very lucky. You don't have to have the B belt put you will have to remove the TB if you want to replace it.

 

[kre8ive_kustomz]

ok, i replaced the b belt, my manual tho doesnt show where to align the arrow up to and i didnt see any on the block(only shows the 1.8 motor)..... there was a small grove that goes between the timing belt cover and the block facing the front of the car, thats what i ligned it up with. i did all this by wiping off the block, i will try today by spraying degreaser on there. this is all driving me crazy but im gonna go get at it again. thanks all

 

[luv2rallye]

ok, i replaced the b belt, my manual tho doesnt show where to align the arrow up to and i didnt see any on the block(only shows the 1.8 motor)..... there was a small grove that goes between the timing belt cover and the block facing the front of the car, thats what i ligned it up with.

Yes, align the arrow on the front balancer shaft sprocket with that notch on the block while aligning the crankshaft sprocket (or backplate notch) up to it's mark at the same time. See steps 18-19 here: http://www.vfaq.com/mods/timingbelt-2G.html. Attached is a pic of mine (99 GST) all aligned.

 

[kre8ive_kustomz]

i just dont know what to think anymore, cam & crank sensors, ecu all belts good now yet she wont start. i would assume that since i have spark and fuel pressure the injectors arent pulsing...... is there a hiddin fuse somewhere for the injection? i checked all fuses in my under dash fuse panel as well as the one under the hood, all fuses were fine. relay maybe? i really dont know, all i know is i just put another 600.00 inta a car that still doesnt run. what else can i check that would cause injectors not to work?

 

[notractiongst]

there is 2 fuses in the fuxebox under the hood that MIGHt stop the injectors from working ...not 100% sure but go aheadand check see if they're blown

 

[luv2rallye]

Check if you have voltage on the injectors. One side should always have voltage (it connects to the MFI relay thru a resistor). The other side has voltage until (and while) the injector fires which is when the ECU connects this wire to ground (thru an ECU internal power transistor). So this other side is pulsed to 0V for a short time (injector firing) but is at 12V for a longer part of the cycle time (injector off). On a voltmeter it will read an average of this so it will read somewhere between 0-12V (while cranking/running). If your not reading any voltage on either side, check the MFI relay and it's 20A fusable link (labeled MFI, MPI, or Engine) in engine fusebox and the resistor pack and wiring/connectors on all of these. If you get 12V on one side and the exact same 12V on the other side, then either the ECU or injector wiring to the ECU is bad. The injectors should click if they are working.

 

[kre8ive_kustomz]

well, i went and checked the voltage on the injectors..... assuming i did it right.... i hooked the leads up then turned the key on..... nothing happened on any injector so i tried the start position. the highest voltage i got was 10.1 for a milisecond, otherwise that one and all the others averaged between 0 and 2.4v..... i know this is an average but it should be higher than that right? yeah, but i didnt get any reading on any of the injectors without trying to start the car. oh yeah, checked the fuse and it was fine. any other ideas? i have been out for a while and thanks for all the help, i dont even know where to start.

 

[armandovivoni]

since you already changed cam and crank sensor, go ahead and try with another ecu and see if the voltage on the inyectors is the same.

 

[kre8ive_kustomz]

i will try that right now, i have that extra ecu i bought cuz i thought it would fix the problem

 

[kre8ive_kustomz]

ok, went ahead and tried the other ecu, nothing happened, everything the same.... im goin to trace the two wires from the two injectors that dont go into the car harness and see where they go, see where that leaves me.

 

[kre8ive_kustomz]

ok, i think im getting somewhere now, i checked the injectors again, instead of using the two wires from each injector i used my meter grounded off the battery, this way i got a positive 11.80v off of each injector with just the ignition switch on, not trying to start it. i got hte same reading off of the resistor harness too. any ideas would be extremely helpful

 

[luv2rallye]

I'm sorry - I thought you knew voltage checks always have the negative voltmeter lead connected to ground or battery negative. You say you have 11.8V on the injectors (I assume on both injector wires?) with key on but not started - that's good. What is it while cranking? (Note you can stick a safety pin through the wire insulation to contact the wire inside and connect voltmeter positive to the pin to get a reading without disconnecting anything.). I just measured mine while engine running and both wires are 13.5V. So it looks like the "fire" pulse is too short to even see with a voltmeter.

all was good untill i disconnected the ecu, now it wont fire at all

This made me think. Sometimes the wire pins in the ECU connectors become unlocked and push back into the connector when you push the connector on. They then don't make contact but it looks fine when you pull the connector off cause they got pulled back into position then. You might disconnect each ECU connector (disconnect battery 1st) and try pushing on every pin to make sure it's locked - on both halves of the connector. Since you have voltage, it's sounding more like a wire harness, connector, or ECU problem. Also check all your grounds (battery to engine to body) to make sure they are clean and tight.

 

[bfdahl]

what would cause the puel injectors not to pulse? my check engine light came on about 3 months ago and all was good untill i disconnected the ecu, now it wont fire at all, i have pressure at the rail but nothing from the injectors..... i replaced the ecu, wasnt that, my manual says that "the ecu uses the cmp to determine the position of the #1 piston during its power stroke, this signal is used to calculate fuel injection mode of operation.... if cam signal is lost while the engine is running the injection system will shift to a calculated injection mode based on the last injection pulse and the engine will continue to run"..... i assume that disconnecting the ecu lost the stored memory setting IF this is the problem, i dont really know anything about this so i was wondering if anyone has had similar problems or heard of this problem before. also, this car has both a cam and crank sensor, but isnt this problem less likely to be crank sensor i had one go bad once and the truck didnt get spark, got fuel. any help appreciated.....

Pulling the code would have been a nice thing to do before unpluging the ECU. you need to see if you can get your hands on a "noid" light to plug into the injector connector and see if it pules while crancking, if it dose not flash you may still have and ecu problem.

 

[steve]

So it looks like the "fire" pulse is too short to even see with a voltmeter.

When cranking or at idle the injector pulse width is only a couple of milliseconds long. Most multimeters aren't going to show anything. Noid lights stretch the pulse so you can see it. I have an old 10Mhz Navy surplus osciloscope I keep in the garage got general testing and a couple of cheap multimeters that will read pulse frequency and duty cycle for quick checks.

Steve

 

[kre8ive_kustomz]

ok, first thing i checked today was for the wires in the harnesses, all four harnesses looked god, just to be sure i opened the back of them and pushed on them with a lil screwdriver. i even tried some dielectric grease on them, didnt work. battery is dead now so i will check for voltage and with the noid tomorrow after work. i bought a noid light a few days ago but im not sure if its the right one, but its the only one autozone had that wasnt for gm..... this one says for bosch port fuel injection. and thanks for sticking with me with help on this one guys, i really appreciate it.

 

[kre8ive_kustomz]

well, i tried those other 2 things, got nothing off the noid light, it might not have been the right one. as for the voltage, with the key on not starting it was a flat 13v, trying to start i was ranging between 10.20 and 10.87v, i didnt understand how i jumped from 11.8 last time i tried till now but then i realized i was jump starting the battery. must have been a long day ...... but anyway, thats where i am, i think steve said it should be at 13.5v when trying to start, i was going to test my 99 to see what it is but i dont know it will be the same as its an 420a and not a 4g63. i think i'll trace the injector wires and se if i find any problems, if anyone has any ideas please let me know, thanks again all

 

[steve]

I think steve said it should be at 13.5v when trying to start.

Your battery voltage will drop while cranking because of the large current draw from the starter. What I have people look for is whatever battery voltage thay have at the injector to make sure power is reaching them. The only time I would say to look for > 12v is when we are testing that the car is charging. Luv2rallye memtions 13.5v but that was because his engine was running and the alternator was charging.

Steve

 

[kre8ive_kustomz]

wow, even though she sounds terrible its great to hear her run..... a few weeks ago i bought some new ngk plugs for her, since i was upset with her and didnt feel like doing anything cunstructive i thought id put them in, i pulled the first plug and smelled gas.... i was happy, so i went ahead and changed them and she started almost right up but now it sounds like a big block with huge cams...... in my book it says if the b timing belt pully is off rotation it will run irratic, any ideas if thats iratic? ..... thanks again for all the help

 

[kre8ive_kustomz]

i might have put the pully's out of timing, my book doesnt have diagrams of the 4g63 so im unsure..... now im in hell, she runs but i tried to leave my driveway and she just wouldnt accelerate. i moved the rotation of the b belt pully and it didnt make a difference at all. anyone knows where i could find a belt pully diagram for a 95 tsi with a/c id appreciate it. thanks again.... forgot to mention, oil smells really hot and shes smokin like a banshee

 

[steve]

You sure your firing all four cyls?

Try the VFAQ site for the (I assume) accessory belts and the 2G timing belts.

Steve