TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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Ok, so i have searched for something related to my cars issue but nothing.
when i try to start the car for the first time after about 5 hours of sitting it just cranks and cranks then eventually slowly starts. I do wait for the fuel pump to prime and still i get the same thing. even when the engine is warm it takes a while for it to start. timing is set to stock at 6*, everything is new except the coil but there is no miss or anything to lead its bad.
I have cam and head modifications currently running on a stock 5spd chip but it runs good, idles at 900-1000 rpm. so is there anything i might be missing?
well related to starting your tps must be closed if its adjust incorrectly IAC valve wont shut, so u could check that check your feul pressure at the rails after its been sitting see how much psi the priming builds
ok, my tps was a little off, it read .61 volts so i adjusted it. although i think i need to open the butterflies a littler more because the idle was at 900-1k now its at 750 but when im slowing down and release the clutch the rpms drop to 6-500 and wants to stall and it doesnt always stay running. yeah the one time it stalled i was going around a turn into a parking lot and luckily no one was there, then after it didnt want to start. it sounded like the timing was way too advanced even tho i didnt touch the timing. once it cooled down a little it started up. still does not start easily.
My timing is 8 9 degrees as the base. and the advance tops out at 39-40. too much? too little?
yeah i dunno, its the same hot or cold, it takes forever to start then idles at 1300-1500 rpm for about a minute then idles down to 900-1k. It almost seems its flooded a little. maybe ill unhook the cold start injector connector and see what happen. after running and it sits hot for a min or so, there is a strong presence of fuel but there are no leaks and its not coming from the canister, its def on the top of the motor.
Sounds like the injectors are leaking and flooding the motor. Very common on the eariler bosch injectors used from 85 to 88. Check your fuel pressure on the rail and watch how fast it takes for your pressure to bleed down. If it bleeds down to zero very fast the injectors are not holding pressure and flooding your motor.
The fuel smell and harder starting is normally one of three things:
*cold start injector malfunction
*fuel injectors leaking
*fuel pressure regulator leaking into the plenum, via vacuum line
Well i hope my injectors are not bad, seeing as i just put in a brand new set of bosch 3's from FIC. I did have an exterior leak but it was fixed. I have a AFPR and the insides are new. Ill have to try out the 9th injector, im not sure if it works or not. Its raining here so i cant do anything today
ok so i have not touched the car all day, before starting it i disconnected the cold start injector. Same thing, still took the same amount of time to start about 8-10 seconds of cranking then a very lazy start up like always
i didnt pull off the vac line but i did about a week ago and it was dry (when i changed a lifter) the car has been hard starting since i got it running.
ok so i have not touched the car all day, before starting it i disconnected the cold start injector. Same thing, still took the same amount of time to start about 8-10 seconds of cranking then a very lazy start up like alway
If the coldstart inj is failed or leaking, then I don't see how disconnecting it would change anything.
You say you changed a lifter? as in pulling the intake and distributor?
If the coldstart inj is failed or leaking, then I don't see how disconnecting it would change anything.
You say you changed a lifter? as in pulling the intake and distributor?
yes, if anything changing the lifter helped the motor because i put on fresh gaskets and fixed a stripped runner bolt so now everything seals correctly.
I dont think the cold start is leaking... the rail holds 42psi for about a solid minute then very slowly falls which by the gm manual is how its supposed to work, and when i was looking for a leak a while back i had the rail pressurized and nothing was coming from the cold start or any other injectors. (the fuel pump was bad that time).
another strange thing is after its been running for a while and its hot sometimes it will stall randomly and will not start until its cooled down a little. but when trying to restart it, it seems as if the timing is super advances as to where my starter wont even move the motor. but when it cools down a little its fine.
btw i have twin fans running on a aux switch with a 180 thermostat and one of my fans is controlled by the computer as a back up but they are both on with the switch regardless of computer or ignition. so the motor never over heats.
Sounds like the injectors are leaking and flooding the motor. Very common on the eariler bosch injectors used from 85 to 88.
+1 On that problem here. But mine did it after it was shut off for 20 minutes +. If it sat overnight it would still start good. I had them cleaned and flow matched at Cruzinperformance and they were great until I took them out this year for my new setup.
__________________ 1988 IROC-Z / 2007 R6 (Full exhaust | PCV | Flush Mounts |Tinted Windscreen | Fender Eliminator | Frame Sliders)
L98 with a little AFR, and a bit of comp cam (316 rwhp). - [Idle Clip]
no doubt in my mind i would have tested that but as i said i have brand new flow matched bosch 3's from FIC with less than 500 miles on them. actually the whole top end of the motor only has 500 miles on it. bottom end is about 1300 or so. So i really dont think they are bad or leaking. even when the motor is hot it takes a little bit to start
I had that problem and it had to do with the cold start circuit just not working at all... it would turn over and over and finally chug to life. i burned a chip with the startup table modified to add the fuel much earlier (like the more modern cars w/out 9th injector) and now it starts within two-three cranks every time.
__________________ The only difference between genius and stupidity is that genius has its limits - Albert Einstein
yeah it probably does have something to do with that. Sometimes when its warm it starts up nice (within 2-3 cranks) and fires up nicely but most of the time no. I really need a tune on this car because of all the mods that are done to the motor. im surprised it runs this well without any tuning.
but unfortunately my trans is basically shot. it grinds into every gear and leaks out the output shaft really bad. so i need to find a replacement soon before putting money into something else