mark kibort

makes sense...... and I could imagine this could damage rings and/or ring lands.

.I guess the question is, how much fuel is dumped per cycle if we don't have a wide open injector or injectors.

Im not guessing here what is wrong, but certainly not an expert either. just trying to rule out the obvious .

I think what is happening, is that the car is not running because the fuel pump primes and then the ECU is not being told the car is running, so no power to the fuel pump relay, and hence no fuel pressure. (proven by the fact that I can start the car with jumper and have fuel pressure regulated at 45psi.) I would feel confident that something electrical is causing this, if it wasn't for the fact that one time the car actually ran , billowing out black smoke with no fuel pressure...... jumpered the fuel relay, pressure was there, but it wouldn't start. after all this starting and testing, there was fuel coming out of the exhaust connections.

I have to go over there and do the tests to really narrow down its not one of the components causing this issue.... leaning toward some kind of electrical connection due to the tach not getting a signal when it was kind of running with no fuel pressure and lots of black smoke.

when he pulled the plugs a few days later, they all smelled of gas pretty bad.
the fuel pump jumped and then the engine cranked, produced no gas shooting up out the open holes.

Speedtoys

You could have a complete FI refresh done in a good weekend, including testing some wiring, if you wanted to.


Otherwise..this is just automotive peer pong.

mark kibort

well, that aint going to happen on the owners budget... we are going to find out what is wrong the old fashon way... just figure it out.
its had a lot of things wrong in my opinion.... im just used to these cars running perfectly!! his has smelled of gas, hard warm starts (could be that leaky damper or 4x out of spec MAF). but what we have now, is something electrical , I think in the fuse panel, but don't know until I show up with my meter and start doing some testing.

don't think its the RRFR because it holds proper pressure
FP relay, as it buzzes on start up running the pump for a second
fuel pump, although it doesn't hold pressure but that is probably just the check valve.
and the dampers cant leak enough to cause this issue of just plain starting.
computers are both checking out good.
the lack of a Tach signal is the telling sign its something deep in the electrical relm If I was to venture a guess.

GregBBRD

EVERYTHING described here sounds like the injectors are being held wide open...or at least some of them.

To do that, one/both of the injector circuits simply need to be grounded OR the electrical system is "seeking" a ground and is getting it through the injectors.

Go back to what the owner was trying to do, just before this problem...and undo whatever he did.

If he pulled ANY relays....take a copy of the part numbers and location and make sure all the relays are in the proper position. There are relays that if swapped, will not allow the car to start again, until the problem is corrected.

Make sure all the electrical plugs at the bottom of the relay board are plugged into the correct position. (A to A, B to B, etc.)

If he took loose the main ground above the relay board, make sure that he did not "drop" one of the grounds....especially the ones to the relay board.

This problem is going to be something stupid, like the above. Stop looking for the obscure and check the obvious, first.

Hopefully the engine isn't junk, yet!

Speedtoys

Does it seem wise, just to simply advise him to well, sell it?

NORMAL keep of a 928 of age, costs more than getting THIS simple issue fixed.


My money says that under this owner, it will degrade in value quickly over time...because no budget for the simple stuff.

mark kibort

he LOVES this car, but has no business owning it .... .by our standards.. plus, he has me, that will always atempt to help..... so, its my problem now. uggg
He thinks he has a gold mind.. . being an S4 and a Stick. and he might be right as the 911 values are skyrocketing! but, the 928s will always lag behind, AND he will never sell it, because he believes like the rest of us that this car is the best thing in the world.

i think you are absolutely right. one thing i also agree with , is that starting a car that doesnt start, over and over smells like coming death to me... should we squirt some oil in the cylinders before we install those plugs.... i thin the nxt time we turn this thing over I will have checked for many of the obvious things.

certainly he has been pulling relays... but he was reading something where you can use the horn relay for substitute for LH, EZK and Fuel pump... is that true? i thought they all have other characteristics where they are not interchangeable. anyway, it looks like those relays are after market too.
however, yes, the car did run and no it doesnt, and doesnt run after some fiddling of things in the fuse panel area with his interior light fix and wire splice. so, again, i agree. we have to go back to what he was fiddling with and figure out what could have changed or become loose.

thanks!

James Bailey

I went back and reread your posts...Scot's engine buildup, now installed and bad things Dated 7/01/2005 perhaps it was the first person writing style but sure sounded like you were quite involved with the attempts to start it and the use of the either....as well as the numerous theories and guesses about what could have gone wrong ! The saga just seemed all too familiar. And that engine was clearly damaged, good to know it was NOT your doing.

mark kibort

I remember the day well. yes, lots of theories, but i was in the background and was CLEARLY against any starting fluid techniques that were being used to get it to cough and sputter. 928s, just start up after rebuild and installation. the mechanic was too used to carburetor 911s.
https://rennlist.com/forums/928-foru...ml#post2302389
EDIT: this was the partial rebuild of the euro engine from 928intl. unknown past. it was a 4.7 euro it blew up on the track and had all sorts of gunk in the oil pan. just sat for too long.... 7 years or something and was pretty ugly.. shouldnt have taken that chance . anyway, we took the grenated motor and just put in a new crank, with larger oiling holes (84S) and two new rods and not even changing any pistons or rings. had top of block welded as it had real bad pitting! ring gap was very large as well, which might have been an issue, OR the use of ether over and over again, with big backfires that blew out the rings , or gauld the pistons in the holes from drying out.
had we put on new rings, that might have not happened, but if the damage was caused by the ether, it wouldnt matter... i dont even own ether... the mechanic was trying to get this thing to start and thats how it died.
anyway, that wasnt my doing...... however, it was a good thing, we took it out and bored it out to a 5 liter. all new rings and pistons and its still running today.

Speedtoys

"AND he will never sell it, because he believes like the rest of us that this car is the best thing in the world."


Well, IMHO, he is the absolute death of it. The existence of this thread, decimates its value as a 928.

It needs a new benefactor to give it any more value than MY 928, which is a chassis on stands at the airport right now.

mark kibort

Ok Folks, to the best of my problem solving abilities, i was not able to get much more out of the situation with this car.

again, it seems all the components that make the car run, are in good shape.
fuel reg seems to keep pressure at 50psi
regulators are ok, they leak a little but no much fuel coming out of one of them . maybe 1 drop.
computers have checked out ok and the MAF has been rebuilt. that didnt change anything.

so, what i did was do a basic check. upon key start position, the fuel pump relay doesnt get a signal. the top curcuite position that should go to ground, does nothing with the key turned on, and has no contiuity to ground. the bottom one has voltage to it. (this is part of the voltage that turns on the relay). the side terminals give a voltage when the key is turned.. so,if i make a ground for the top terminal...... the key is turned and the relay is activated and the fuel pump runs. the car floods out while starting.

without the plugs in the holes, if i do this test and then remove the fuel pump jumper, lots of fuel is being pushed out the holes in the form of a fog. plugs have spark on both sides when the key turns. it wants to start with fuel and spark, but wont run and just floods out.

Tach is not working and doesnt move when the car does catch occasionally, it bucks and misses and then dies and floods out.

one time, i turned the key and the injectors started fluttering full speed. you could feel them turning on and off, just with the ignition in the on position. (no fuel applied as i had the relay out) . turn off the key and then turn it back on and it didnt do that again.

there is some ground problem i sense.

I also just took that ground of the top terminal of the fuel pump relay socket, and then traced the wire to the first major wire bundle on the right of the fues panel. the upper most left pin is that brown and red wire. if i ground that, the fuel pump relay activates.

somehow , this fuel pump relay is not being activated from the ECU and is probably also responsible for the TACH not working too.
I thought by jumpering the ground at the wire bundle, it might complete the circuit for other elecments needing a ground, if the ground was dislodged. However it did nothing but make the engine flood out, as did with just using the jumper on the fuel pump relay socket.

another interesting element..... turning on and off the fuel pump relay, caused the fuel pressure to remain at 50psi or so even with the pump off. no decay of pressure. it did that one time, and then the next, the fuel pressure would slowly go down after about 5 -10 seconds. weird. its like there is an injector that is leaking down, intermittently.

ok guys, where do i look next??

hb4

That brown/red wire goes to the LH (nowhere else) and is pulled to ground based on the LH logic, one piece of which is an RPM signal from the EZK. Find out why the LH isn't pulling that circuit to ground.

Injectors fluttering with the ignition in the first position is often a sign that the LH is faulty. Ask me how I know.

James Bailey

did not reread this whole thread but have you tried a known good LH brain (like from your car) in this car ???? or his brain in your car ??

mark kibort

No, but we sent the brains to Rich, who verified they were good. sounds like they might not be.........I dont think i want any of my brains touching this car. sorry, just too risky for me. (scared of the unknown... not my expertise)

mark kibort

so, that brown/red wire is connected to ground via the LH? and where does the RPM signal come in from the EZK? the brown and red then goes to the LH and is grounded there. got it.... that means if it is grounded , that low currrent flows through the relay to close the contacts and flow current to the fuel pump. this sounds like the problem... but, im wondering about the injectors fluttering , if that's related.

yeah, those injector fluttering was kind of strange. they did that until i turned off the ignition. tried it again, and it didnt do it..... this happened one time before too during our tests. LH faulty... Hmmmmmm wonder how Rich's test could have missed this.

mark kibort

so, that brown/red wire is connected to ground via the LH? and where does the RPM signal come in from the EZK? the brown and red then goes to the LH and is grounded there. got it.... that means if it is grounded , that low current flows through the relay to close the contacts and flow current to the fuel pump. this sounds like the problem... but, im wondering about the injectors fluttering , if that's related.

yeah, those injector fluttering was kind of strange. they did that until i turned off the ignition. tried it again, and it didnt do it..... this happened one time before too during our tests. LH faulty... Hmmmmmm wonder how Rich's test could have missed this.