(for those who don't know i have an Ld9 heavy N/A build.. see my mod list)
so the motor is in... the injector constant has been changed... the motor struggles to start and backfires through the Throttlebody.

I know the cyls have been flooded with fuel... the spark plugs were dripping wet.. i cleaned them, cranked the motor over without them a few times to blow out the cyls, and then put them back in, the car went from just cranking but not firing to barely firing, running for like 2 sec and dying with a backfire. Pulled the plugs and they were dripping wet again. So i left them out so that the cyls can air out over night.

Now when we changed the injector constant, we noticed that i had two codes. Cam shaft Position sensor code, and IAT high resistance code.

My tuner and Jeffie thinks i may have a timing issue as well as a fuel issue. I know my timing is set dead on, however i do not know if dead on is the correct position for the cam upgrade (Clyde??) Also im 99.9 percent sure the intake cam has the CPS pad... however i don't have a memory of seeing it (nor do i have a memory of not seeing it) (Clyde again for this one =)) I'm pretty sure its there, but at this point i need to find out everything that could be causing my issue and start ruling things out.

It may also be possible for my Cam shaft position sensor could be fouled out, or could have fouled out during the initial runs.

The Techs that work with me think my issue is 100 % fuel and spark related or cam shaft position sensor fouled out.

any thoughts?



Edited 1 time(s). Last edited Friday, March 12, 2010 1:51 PM

I had this problem with my 2.2 OHV though not the same it ended up being a bad O ring on the injector, allowing it to stick open and constantly dump fuel check those and check your fuel pressure regulator, but ive havent build up an LD9 so im just taking a stab in the dark here


Erik Packard

jeffie mentioned the fuel pressure regulator as well... the injector o rings are brand new though...

fuel pressure at the rail was spiking between 55 and 60 psi when running... after cranking it with no start, it dropped as low as 42 PSI... it came back to 50 PSI after i cleaned the plugs.

The only time you have to worry about the injector leaking fuel in the cylinder from a bad o-ring is when you have side feed injectors... The ld9 has top feed injectors. Sounds like a timing issue or maybe a injector sticking wide open. That would cause your fuel pressure to move around like that..

Thanks for the lesson about the LD9, like i said i havent worked with them so much just the LN2 and the eco, and your right the pintles inside the injector could be sticking open i overlooked that idea.


Erik Packard

i honestly think its a mis-aligned timing issue. rip the timing cover off and check it out. as far as the fueling issue goes... i have no ideas.

the CPS could not even be there and the engine would work just fine. however... i am pretty sure that cam has the pad on it.



We all need somebody to believe in something...

so i need to see where timing needs to be at, cause right now i know its dead on... and we spun the motor by hand twice and the marks stayed aligned.

Hows your crank position sensor sir?

only 2 years old... im not throwing a code for it, and i put it in correctly.

I ran those .430s timed exactly as the stock cams were. There is no CPS pad on them and it only ever gave me a hard time on a hot soak restart. I would have a long crank, but that was it. If all the timing marks are lined up as they are supposed to be and the crank sensor is working correctly (shouldnt even fire if its crapped out) the timing is not the issue. If there is any possibility it is due to a damaged CPS just unplug it as its doing no good anyways. I suspect it is either a fuel or spark issue.

i assume then that the CPS threw a code because there is no pad, and not because of a failure? How do i keep the CEL off?

Turn the code off in HPT.

clyde... i could have sworn you said they had the CPS.





We all need somebody to believe in something...

When I had my 2.2 and I installed the 1.6 ratio roller rockers I didn't do the lash adjustment right the first time. Actually I just tightened them down instead of doing it the right way. This made it not run and made it backfire through the TB since the intake valves were staying open.

I vote for it being a timing issue. I have full faith that you probably put everything together right. Any chance it could have jumped timing?





i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick

thats a possibility.. i'll know as soon as i go on lunch and do a compression check...

i really need to know what the injector constant should be so i can stop flooding the cyls with fuel... its hard to diag like that

I posted in your other thread about injector constant. Is it a stock FPR? Have you checked it to mkae sure it is good? if not put a vacuum pump on the nip that the vacum connects to. See if it holds.



FU Tuning

Compression test showed 270 PSI across all cyls.

its a stock FPR. I know the tune is right, its set to .138

i have a few different theories at the moment...

first of all, the gas is 6 months old... its possible the octane is sitting around 70 instead of 93... so i'm going to put octane booster in the tank.

Second of all, the plugs may be fouled out from being washed out with gas, so imma get some cheap plugs and throw them in there.

i'm going to let the cyls dry out again from today, and re oil the cyl walls because the gas probably washed them out again after the compression test.

-------------------------

Now questions... does the crank position sensor regulate ignition timing? If not, what does?

Speedline02 (GME Chat!!) wrote:
Now questions... does the crank position sensor regulate ignition timing? If not, what does?

That's actually its primary purpose...so, yes.




I have no signiture

ok... nice... so what is the purpose of the cam position sensor?

and how does 270 PSI sound for compression... considering my upgrades, does that sound about right or is it too high?

EDIT::: UPDATE:

played with it a little after work... we took the spark plugs back out, once again dripping wet with fuel... we took one plug and introduced flame from a lighter... no burn what-so-ever... and the fuel does smell stale... leading me to beleive that the gas has fouled out on me.

thoughts?

i plan to get 4 cheapo spark plugs and some octane treatment... if this does not work, we will drain the gas out and get some fresh 93 octane gas to put in the tank. I'll get to touch it again in the morning.


Edited 1 time(s). Last edited Friday, March 12, 2010 2:40 PM

Gas being 6 months old is not a isse, and is not likely that low on octane. I have run a car with 4 year old gas no issues.

Have you tested the FPR? Do you know what your fuel pressure is?



Edited 1 time(s). Last edited Friday, March 12, 2010 2:39 PM


FU Tuning

i just edited my last post...

fuel rail pressure is averaging around 50 PSI

i do not have a vaccum pump to test my FPR

um holy hell 270 psi?! that is A LOT.

pauls is only like 225 when hot.

dear god dood.



We all need somebody to believe in something...

so what does that tell you??? is too high of a compression going to cause a problem like this?

hell no.

you have a lot of CRANKING PRESSURE.. at most it would make the starter work a bit harder.



We all need somebody to believe in something...

There it is... across every cyl