**PLZ HELP!!** 1997 WARM STARTing Problems

[ROCKART]

Ive been having this problem since April when I did three major changes to my 1997 GLE in one day: 1) Installed Thermal Spacer Kit2) Installed Budget (LSS) Y-Pipe3) Replaced Valve Cover Gaskets and Plug Grommets

I want to say that I had absolutly ZERO problems with my car before that day of installs. I am 99% sure it is a direct result of something that happened during the work - most likely the thermal spacer kit was installed poorly. The reason i say that is because i know at least 10 4th gen maximas with this exact spacer kit and have no problems with it. and of course there are hundreds of maximas with aftermarket Y Pipes...

so this is either from the spacer kit or the valve cover replacement or a combination of the two

!_!_! NO ONE CAN FIGURE THIS OUT, NOT EVEN THE MECH THAT HELPED ME WITH THE INSTALL. Ive been posting on three different forums for 2 months, been to 4 Nissan dealerships, talked to a whole crew of performance racers, etc. Im stumped....

this seems like an exhaust/fuel issue but its hard to be sure....

THE EFFECT:

--> if i leave my car parked overnight, or the 9 hours i spend at work, and i come out to start it, it starts fine. by fine i mean the car ignites quickly, catches quickly, and the RPMs shoot up to the normal starting parameters (~1200-1500). i refer to this as a "strong" start.

--> if i drive my car around for 30 minutes or so, and then turn it off and turn it back on immediately, it will start perfectly fine, as if the engine was cold.

--> HOWEVER, if i drive my car around for 30 minutes or so (and get the engine hot), and then turn it off and leave it for 15 minutes, and then come back to start it, it starts VERY VERY weakly. by this i mean that the car ignites quickly, and it catches, but the RPMs sputter around 200-300 for about a full second before going up to the ~1200 mark.this causes the car to shake a bit. twice, in the three weeks this has been going on, the RPMs sputtered around the 200-300 mark before just giving out and stalling the car.

somehow the temperature of my engine is causing something to either not read or feed properly.

THE CAUSE:

**some of this stuff may be inconsequential, because we found whatever problem it was and fixed it, but i figured i would include it in case it could have caused another problem that im not thinking of.

three weekends ago i spent the day at a Nissan dealership (with an org member who works there) installing the following:

a) NWP Thermal Intake Spacer Kit (one throttle body spacer, two lower intake spacers and one plenum gasket spacer)b) Budget Y Pipec) Replaced Valve Cover Gaskets

and then some other random things:

d) Replaced Rotorse) Replaced Charcoal Cannister and Valve (to get rid of my CEL)f) Flushed Brake Fluidg) transmission Drain/Fill

initially, after the 7 hours of labor was complete, when we tried to start the car up, the idle was very erratic and jumpy. we discovered that in the process of redrilling those manifold brackets, and putting the IM back on, the EGR gasket slipped a little and allowed a leak. we removed the IM again, redrilled the brackets and corrected the problem. the idle was normal once again.

the next few days, i began to notice that when i was sitting at a red light, my RPMs would be at 600-650 and then drop down to 550 and 500 and make the whole car shake and rumble. i would have to give it gas to get it to sit back normally (this was from a plenum gasket leak, but i didnt know it at this point).

THE SUGGESTIONS:

im still not sure if this is from VCG or spacer kit, or a combination of the two. my guess would be the spacer kit, and a faulty install, but its hard to say.

these are the suggestions ive gotten, both from org members and local people:

1) ECTS (engine coolant temperature sensor). this would most likely be throwing a code if it was broken, plus it would be pretty strange for this to coincidentally break on the same day i was putting all this aftermarket stuff on. the nissan mechanic who did this stuff with me said hes never seen one fail in over a decade.

2) Exhaust gases getting caught in the pipes (this is from the Autozone employee). basically, now that i have a high-flow y pipe, but the rest of my exhaust stock, the exhaust is getting caught up around the main cat and choking my car. this would make sense, because only when the car is warm would gases still be in there (when its cold, the gases have had time to dissipate) but, ive heard from a number of maxima owners who say they used an aftermarket Y with stock exhaust and had no problems.

3) Grounding Issue. the org member that helped me with all these installs thinks that putting the spacers in has somehow eliminated a ground for the engine. he thinks that the upper IM and lower IM, that were touching before the spacer kit, ground off each other, and now that there is a plastic 1/4 spacer between them, they can no longer do that. we ran a jerry-rigged grounding kit from the ECM grounds to the neg battery terminal (actually to try to fix the weird 02 code), but that hasnt done much. he said he would try grounding the bottom of the oil reservoir to the transmission case as well. but why would this only happen when the engine is warm? and then there are about 20 other org members with these spacers and no grounding problems. i HAVE SINCE PUT A HYPER GROUNDING KIT ON MY CAR, 8 POINTS, AND IT HASNT CHANGED ANYTHING.

CONCLUSION:

im sorry this is so long, but i am ****ing stumped here. no one seems to be able to figure this out. and quite frankly, knowing what i know now, and how much money ive dumped into these "bolt-on" mods, i would NEVER have done it.

the added power is no where near worth all these problems. i would have thought for 800 plus dollars of experimentation, i would be making my car stronger and faster, but it has made it weak and tempermental, for not that much more hp. im pissed. i should have just left it stock.

****last night was the worst start ive ever experienced. ill give you guys a detailed account, in case any of this has to do with anything else.

- drove 30 miles on the highway to my house.- was in my house for 15 minutes and decided to drive to the video store. - started up my car and it had a semi-weak start, not bad tho - spent 5 minutes in the video store. started my car again, same weak start, but not bad- drove from there the 5 minute drive to the supermarket. spent 30 minutes in the supermarket.- i pack my groceries in my car, go to start it and it ignites, catches, but then just gives out around the 200-300 rpm range. i try again, goes up to about 400 and gives out. - let it sit for 15 seconds, try again and it BARELY starts. the weakest of them all.....

so i guess the "peak weakness window" is like 30 mins sitting after getting the engine hot.

what else could be causing this?

- Vapor Lock possibility? Gas line near something hot? - Improper crankcase ventilation? PCV hose damaged/not secure? - IACV damage/miscalculation? (having trouble “keeping up” with warm motor)

im lost . please help. ask whatever questions you need.

and if there are any of you near south florida, i will PAY YOU to help me figure out this problem

thanks
Modified by ROCKART at 1:10 PM 6/25/2008

[MaximA32]

I would see what it would cost to replace the front tube assembly of the exhaust. It's the part that goes from exhaust manifolds to catalytic convertor. Generally, a problem with that particular peice of pipe will throw false o2 sensor codes. Itl could have been triggered by the fact that you installed the after market exhaust manifolds without doing an entire exhaust system that flows as well as the manifolds.

[ROCKART]

yea the o2 code was solved with a simulator from http://www.o2sim.com

apparently its a common code after a y pipe install, because the cats no longer restrict the airflow and too much o2 is hitting the sensor. anyway that problem is solved. i will edit my post above.

my issue here is the warm start problem

any ideas?

[MaximA32]

I would check the EGR tube. It's a little tube from the back of the engine to the bottom of the EGR valve. It gets packed with carbon buildup and what not from the exhaust. I would also check the operation of the EGR valve itself.