I just installed my 30# SVO injectors yesterday and reinstalled my ecm after having it tuned and it drove fine yesterday. Today I noticed the hard starts are still there when the motor is cool (below 160) and now when I backed out and the car started to head back to idle it got erratic a lil bit, the voltage gauge fluttered a lil as did the oil pressure then the service engine soon light came on, it did this just for a small bit then went back to normal, the car performs like normal with the SES light never coming on while driving but when im backing out or coming to a complete stop and taking it out of gear, it flutters and gives the SES light. Anyone have any idea what could be wrong or if I may have not seated the injectors right?? they are all tight and the o rings are in the bores, it seems to run fine any other time, I was thinking maybe a vac leak of some sort??? Any help would be much appreciated.


EDIT:well I just got back from test driving it, this time it didn't do anything, it ran normal. I got on it several times and all pulled strong but the last time I did I suddenly got a horrible exhaust leak or so I thought, couldn't figure out how I did that the entire way home, I get home and pop the hood and checked underneath for a leak sound to see where it was coming from, nothing. sure enough I go to check under the hood and blip the throttle a couple times and immediatly hear a hissing sound coming from the passenger side. the AIR hose im assuming thats what it is, that is on the manifold completely split in two. its giving off an exhaust leak sound and is very annoying, Could this be what was causing the hard starts and rough idle coming down?? Im naturally assuming it was already cracked but I finished it off with the abuse today. Looks like its time for the LT's either way. I was debating on the GMMG or headers first, looks like it'll be the headers.

 

There's a black conical check valve in the metal tubes that go into the exhaust manifolds. The AIR system supplies air to the check vavles, and connects to them with rubber elbows/hoses that clamp to the check valves. It this the hose that split? If so, it may indicate a severely leaking check valve, that allowed hot exhaust gasses to flow backwards through the check valve. That overheats the hose and melts it. A leaking check valve could have a negative affect on the way the engine idles.

http://shbox.com/1/diverters.jpg

You also need to have it scanned to determine specifically what turned on the SES light. That might point you to the AIR system, of some additional problem.

 

Thanks for the reply injuneer. The part that cracked is the actual metal tube that goes into the manifold on the passenger side directly under the diverter . It literally split directly in two. I'll see if I can find someone around here that will scan it without arguing with me for 10 minutes about my car being OBDII when its actually OBDI. I wonder if this can also have a negative effect on the hard cold starts?? It only does it when the car is cool, when its warm it starts right up. WOT starts do nothing and priming the pump several times does nothing, so I don't think its a fuel problem. I think its a vac leak of some sort and this one is my prime suspect right now until given reason to not blame it. I have good fuel pressure also. I thought gas was in the oil but I think im just thinking I smell it, cause its not real strong just sorta seems like a gas smell to me. Reading maksiks thread kinda has me wondering if I actually smell gas at all now though.

 

well I see after reading a few threads that the AIR system is only for cold start up. So I guess im starting to wonder if it's even possile for it to be whats causing the hard starts since once the A.I.R system is deleted it wouldn't matter anymore. I guess the only possible way is if its the leak while the system is still attached and functioning (or attempting to) that could cause hard starts. Any ideas or opinions on this matter?

 

wow ok, I plan to get it scanned tomorrow but I just drove it again to see what it would do, and this time it drove fine for about a 1/4 mile but when I pulled into a dealership to turn around it bucked a little and the SES light came on, I waited for it to go off and pulled out well once I got up to about 30 mph it did it again and threw the SES and by bucking i mean literally almost stalling, jolted me a lil. Now im getting concerned. I hope this is all relative to this A.I.R situation. Any ideas maybe on this? Could it be from a bad install possibly or maybe dirt got into the bores before reinstalling the injectors? This must be pretty abnormal considering the attention this thread is getting.

 

If I understand correctly, the metal tube that screws into the header has an open crack in it. Not good. As the exhaust flows by the tube opening, it induces a vacuum and pulls fresh air into the exhaust system. Totally screws up the O2 sensor readings on that side. And with the leak so close to the head, you run the risk of burning an exhaust valve. When the O2 sensor sees the air being pulled in, it adds fuel to richen the mixture... fuel the engine doesn't need. Might explain why you may have fuel in the oil.

I think in one of those posts you indicate the AIR system has been deleted. The "fix" in that case is to pull the AIR tubes out of the headers and plug the holes up so there is no way for air to leak into the system.

Not sure if this relates to hard starting, although if you screw up the long term fuel corrections bad enough, it might be enough to make it hard to start because its too rich. And, it might be reading the air leak as a lean condition that is severe enough to set a code and turn on the SES light. Might want to get it scanned to help pin down the problem.

 

nah I don't have the AIR system deleted, I will here in a couple weeks when I get my headers and install them though. And I'll be pulling all that junk out of there then too and plugging up the holes. I guess this is just so coincidental that this just happens a couple days after my ECM tune and installing the injectors. I was kinda wondering about a clogged cat, but it just seemed odd with the timing of everything I guess.

 

OK injuneer, I tried scanning it yesterday but the autozone here only does OBDII cars so I have to try and find someone else but in the meantime while sitting at work last night I was thinking hard about some things, and im new to this but understand a lil about a motors reaction to lean conditions so, when I did the install I was prying at the cross pipe on the rails behind the throttle body and the injectors were seated pretty well and it made a slight dent in the cross pipe. Could this or possibly somehow I didn't seat the injectors well enough into the bores and this could be causing a low supply of fuel to the engine? Or is it possible I have a weak fuel pump and the 30# injectors could possibly be too much for the stock pump???? Im not sure about that type of thing, but I cant help but feel the car is running lean. Cause of the excess heat and stumbling but yet I still have good performance all the way to redline without any hesitation except for those two times it did that and I haven't driven it since. Could a lean condition cause enough heat to bust that tube?? Or would that have to be caused by some kind of pressure due to a slightly clogged exhaust?? This is starting to bother me, because the timing of it is just too much for me. All of a sudden after installing bigger injectors I have excessive heat on the passenger side and stumbling causing SES codes. The hard starts have been there since I bought the car. I need to retest the fuel pressure, but would it matter if its something to do with the cross pipe dent or o ring seating?? Since thats after the shrader valve and I'd be testing running fuel pressure and not bleed off after the car is turned off for this situation. I know this is just stabs in the dark, but im just desperate right now for some kind of direction at least to settle my anxiety.


EDIT: I just thought of something else, when I was installing the injectors, I accidentally had quite a bit of fuel dump into the bores, and when i started the motor up after the install, expectedly it spitted and sputtered and had alot of black smoke chucking out of the exhaust which was expected with that much extra fuel causing it to be rich. Well it evened itself out and ran fine, theeenn the next day is when I got the small stumbles at idle with SES lights until I ultimatly ran it hard and busted the tube which now causes a bad lean situation that makes the car stumble hard and throw SES. The point im getting at is could I have fried an O2 sensor which caused it to run hot and bust the tube in which led to the lean condition I think im in now causing the hard stumbles and SES lights??? Bare with me, im just trying to narrow it down even in the dark till I get it scanned.

 

I think I may have found the culprit this morning before laying down, I didn't seat the passenger side injectors right, on the driver side they are all down in there snug and you can't see any of the yellow ring or the black o rings. all you see is the injector itself down in the bore snug. On the passenger side I can see a little bit of the yellow from the top rings on all but the back cylinder meaning they aren't in there snug enough. Could this cause the car to run lean on that side? I know im getting fuel, but with them sitting to high up can it cause some of the fuel they spray to not be burned or maybe it messes with pressure on that side???

 

If the O-rings aren't in the intake manifold, you have giant vacuum leaks. That would cause the PCM to add extra fuel you don't really need, and you'll end up overheating the cat, possibly melting it.

 

well im getting ready to correct it now, the car hasn't been started since I parked it that day it stumbled those two times, so I haven't been damaging it anymore thank god, im putting headers on in two weeks getting rid of all that stuff anyway. So ya think that is most likely what busted the tube. It has to be imo cause everything was fine until I swapped injectors and the passenger side injectors are not seated right and the passenger side A.I.R tube cracked, sounds about right to me, but im not expert by any means. Could I possibly weld that tube back together just to get me to my buddies that is about 15-20 miles away for the header swap in a couple weeks? It wont be driven anymore than that but I still don't wanna run the risk of burning an exhaust valve just in that short trip.

 

You still need to figure out how you generated enough pressure in the exhaust system to actually crack that tube. Its not something that's just going to fall apart for no reason at all. Maybe with all the fuel and air you were pouring in, it was still burning in the primary and both heat and pressure caused the tube to fail.

Temporarily, you could just pull the tube out, and put an M22 oil drain plug in the hole. Or use JB Weld on the tube, and put a small clamp around it to stop it from leaking until you could remove it.

 

ok, now im getting frustrated, I just went out after reseating the fuel injectors and the SES light is coming off and on and the fans kick on when the SES light comes on. Is this something wrong with the MAF??? Also where can I get an M22 plug, just any parts store??

EDIT: I also want to add this is in open loop. immediatly upon starting the car.

 

Its easier to diagnose problem with a scanner, but 9 times out of 10, when the SES light and the fans come on when you try and start the car, its a blown fuse for the AIR pump. If you've had excessive pressure in the AIR tube, its possible the check valve on that side was leaking, and the exhaust gasses got back to the AIR pump. In that case, you could have corroded the pump, it siezed up, and blew the fuse. Check the fuse. If its blown, replace it, and disconnect the harness connector from the AIR pump. As long as there is a good fuse in the circuit, you can unplug the pump and not get an SES light (OBD-I only).

 

cool thanks again Injuneer you're a great help, one quick thing though, would the blown fuse cause the fans and SES light to stay on, or would they come off and on about 5 seconds apart and stay on for about 5 seconds before going back off?? This just happened for the first time today but thats also the first time the cars been started since the day it stumbled.