xsboost90

ok so i recently decided to install some new cambox gaskets as mine was leaking oil from the front down the block and killing my swaybar bushings. While the car was apart i figured i would install my 55lb seimens injectors i bought from Jeremy Hinsel and my 3bar regulator- along w/ a set of Max chips i purchased just for my setup- tial 38mm, 3" LR exhaust, 26/6, 55lb inj, 3bar reg., no cat, stock afm.

installation went smooth, dropped the cambox on, put in my chips,hooked up the injectors and regulator, reinstalled the fuel lines etc...today i got the last gasket for the cambox i was missing from the kit, installed the gear, belt, etc and fired her up. She started right up but had a hell of a miss- i figured the lifters may have needed to pump up. Let it get up to temp, still kinda missing at partial throttle- seemed to clear up when you'd rev it. Shut it off- pulled the plugs. All looked tan, not wet. Ok reinstall my Magnacore wires which have been trouble free so far. Fire it up. still missing. Tryed the pull injector wires trick- seemed like number 3 if i pulled the injector it didnt change idle at all. Plugged it back in- took a long piece of small tube and put it up to the injectors- each one was clicking like crazy! Ok they should be working- not stuck at least. Then i start worrying about when i installed the cambox- i clocked the cam so it was at TDC- the engine was at TDC- somehow between clocking and install, it got slightly off TDC about 30degrees. Anyone know if i had the cam turned and installed the cambox if it would bend a valve by pushing it into a piston that was up, or would it just spin the cam back since the belt was off???

So i drive the car. Runs ok really, like a scalded dog on boost. Rough idle. Took the front of the engine back apart, checked timing- timing belt was dead on w/ the mark on the bottom of the flywheel and the cambox and balancers....ok not that. Cleaned up the inside of the distributor cap to see if it was corroded-not new for sure- put it back together. Nothing. Still idling like crap. Took it down the street- only running on 3 cylinders! Pulled the plugs- all are tan- not wet.

SOOOO...what gives- do i have a hanging injector, do i need to swap chips to see, could i have a bad regulator-doubt that one- or maybe its just my magnacore wires even though i didnt touch them during the cambox swap besides removing the cap...Hm...

xsboost90

ok so i pulled the 55lb injectors and installed my stock injectors. No more miss and runs fine- alittle lean obviously. PUlls very hard! Now...i have a set of injectors that were flow tested on 8/30/07 and were 100% fine- have the sheet right here- why would they not be working now- at least one of them? I pulled them straight from a sealed plastic pouch and put them right into the car.

Rock

Too rich?

fastmover

Hey boost90,
I'm a new guy here, but I thought I would put my 2 cents in. does the car misfire at all rpm's or intermittingly? If it is all the time, you might have a broken valve spring, As a certified Porsche Technician and a 88 951 s owner, I would 1st try swapping the chips and injectors back out since they are probally matched to eachother, if that does not fix it, I would do a cylinder leak down test and a compression test in order to establish if there is a problem with the intake or exhaust valve, during the leak down if you hear air in the exhaust then it's the exhaust valve, air sound in the intake then it's the intake, air in the crankcase (through the oil fill cap) then it''s in the pistons/rings. Other problems could be blown head gasket, or ignition. check for spark, easiest way is to use a timing light and put the inductive pick up on each spark plug wire and watch the light pattern, they should all match in tempo. (keep the timing light wires away from the coil, cause it could interfere with the light signal) If you see a differance then you can look at a coil or reference sensors. I hope some of this helps, by the way real nice looking 951, I like the front splitter where did you get it from?

Fastmover

fastmover

Well disregard my post then, nice car anyhow.

xsboost90

its an AIR splitter- i bought it from a rennlister- you can get them new on www.americaninternationalracing.com though. I'm a former mechanic but sometimes i think to hard about things and its good to get a fresh look at the problem from someone else. It always when you think "no way THAT is the problem its new!" that things are harder to figure out.

fastmover

Thanks for the splitter info, Some times it's easy to overlook the simple stuff.

TRP951

does anything show up abnormal on the zeitronix like crazy AFR or anything else?

xsboost90

well with those injectors the afr seemed really good- but my EGT plug pulled the wires out while i had the dme pulled i guess and now its not working - hopefuly i didnt f- it up too bad. Now w/ the stock injectors it idles at 15.6 afr and only gets to about 14afr at full boost- so the car will be sitting until i figure this all out- hopefully by saturday wheni have a p-car meet.

billthe3

Maybe the electrical connection between one of the injectors and the harness is bad? Like it might have not been plugged in all the way or something?

OZ951

Are you using a resistor with those Injectors ?

xsboost90

no resistors yet w/ the injectors. There was a thread on this- the 55 injectors the resistors are a good idea but not necessary- the larger injectors you need them. I am planning on putting the resistors in but just wanted to get it running right now. Im not sure that its the electrical connection since i had it on off a few time w/ no results - then plugged my old injector in and worked fine.

-im going to do a flow test on the car tonite- four measuring cups, stock injectors vs. new injectors. We'll see if they seem to be spraying equally. Maybe i did have something screwed up.

Chris White

move the new injector to a different cylinder and see if the missmife follows it.
Good to rule out injector vs harness/wiring problems.
It could be that there is a partial failure in the harness and the different impedence/current draw of the larger injectors does not allow the very short signal (idle injector firing) to fire the injector. You could also be approaching the minumum injector turn on time (1.2 to 1.5ms depending on the injector).

xsboost90

i noticed last night that Jeremy had the injectors etched 1,2,3,4 - when i reinstall i'll put them in this order and have someone crank it with them pointed into some paint cups. We'll see if they are all firing or not. Could be time for a lindsey injector harness...

5speed300

I know its already been said, but I had the same problem as you (running on 3 cylinders really rough) and it turned out to be the #1 injector harness clip.