Kenteth

So I have hot start issues. I did a search and found some other people with the same issues, but never really found a decent solution-- at best hit or miss. The fact that the thread titles had little or nothing to do with hot start didn't help much.

This started last month. The same thing was happening the summer before, and the summer before that. Bascialy, cold/cool, the car starts great. You have to let it warm up to get idle (TB Mod, no BAC, ect). If I stop at say... the grocery store and doodle around there for about a half hour, I can come back out to the car and have issues starting.

Generaly, it just acts like its flooded, but tapping/on-off the accel pedal helps get the car started. Once its started, It won't idle on its own (even if the engine is still warm). It tries to studder to death.

The solution... What seems to work is to on-off the accel pedal until you get to about 5k rpm. Then slip the clutch out and get some speed. If you can make it about 250 feet without the engine dropping rpms, you're in the clear. The car will run great until you turn the engine off again for a few minutes.

On the other hand if you're in a parking lot, you have to limp it trying to keep the rpms up even though its studdering like crap until you get to the street, when you do the said 5k clutch slip out of the parking lot.

The hot start happens at least once a day if I'm making numerous stops. I can stop at a drive-through and shut the car off at the order microphone/window and it will start up just fine a minute later. But if I let it sit for 10 minutes or more, its got the hot start issue.

Any ideas guys?

Only thing I can think of is the FPR nipple bypasses the original Hot-Start solenoid and goes directly to the LIM instead. BUT, that was done this march, and the hot start issue was happening years before that.

Thanks!

PureSephiroth

i have nearly the exact same problem as you. I usually have to pull the fuses to unflood it though.

91mazdarx7

i have the same exact problem but i dont have to keep the gas on when i do get it started from everything i found on this issue everyone said clogged injectors almost 100% sure clogged injectors

WAYNE88N/A

Sure you don't want to put that BAC back on there, Kenteth, lol? I've been monitoring ECU inputs the last couple of days, and found out that BAC valve does much more than just maintain an idle, it also energizes on decels, for instance....Do you still have the air bypass solenoid valve on there?

I'm sure you've tried tweaking the idle adjust screw by now, running it out some might result in a higher idle cold/warm, but might help on the hot starts...

Also, have you tried removing the vac source from the FPR, to see if that helps? That would simulate the pressure reg control solenoid working properly in a hot start (dynamic chamber sensor >176*F) situation...

Kenteth

This is actually pretty helpful. I've been thinking about putting the BAC back on since I got the car running again in march (after a 6 month sleep.) I'm thinking I will be putting it back on for the next fall/winter season to have it driveable in the northern climate when the cold wheather hits.

As for the FPR Vac solenoid, correct me if I'm wrong:
DC T > 176*F -------- No vaccum, (atmousphere pressure) on FPR
DC T < 176*F -------- Manifold Vaccum on FPR

Correct?

Does the FPR drop the pressure when it is vac'd or atmousphere?

Also, anyone remember the color of the FPR solenoid/harness?

----

Although I don't think the FPR is the culprit, it is something I'm going to hook back up. Same with the BAC later this summer.

It still leaves what seems to be a common (for many people) problem...

WAYNE88N/A

Correct, the pressure regulator control solenoid valve shuts off the vac to the FPR during hot start, it's the orange one, BTW...That's the only one I left on the rack when I "cleaned up" during the rebuild, because I felt it was needed (and I have no hot start probs). It's got a black/white (12v) wire, and a blue/orange wire (heads back to the ECU) on it...I'd just pull the vac off the FPR during an "episode" for troubleshooting, that should tell you if you need to worry about getting it back on the car or not...

Kenteth

Thanks. If the hot start was a constant issue I could go test the theory, but its inconsistent. I'll work on it morrow though.

EDIT: meh, ill do it right now, I'm just sitting on my lazy bum anyhow...

Tiers

2 words...LEAKY INJECTORS

Our injectors get clogged and leak and spit puddles of gas. Get them professionally cleaned or replaced.

I just went through this and car is once again happy. The injectors were so clogged dirty I cant believe she even started let alone the flooding problem. Of course other things can be the cause but injectors are the prime candidate...

HAILERS

The BAC also opens all the way upon startups......more air.

Kenteth

Everybit will help! I looked at the engine bay and tested a few things. My aux ports haven't been opening, and I just realised my air pump (electronic) has kicked the shooter (DAMN!). Anyhow, thats somethign else i'll have to rework (again). I looked at the BAC port hoping I could do the reinstall w/o removing the DC/TB bc everything is gasket-sandwiched in. Doesn't look like I'll be able to remove the blockoff plate w/o removing the tb though. Maybe I'll do it tomorrow.

Impreza2RX7

Hmm.. Are N/As that different than TIIs? I didn't have to remove jack to take my BAC off..

Kenteth

manifolds are diffrent, the BAC sits under the TB

WAYNE88N/A

[QUOTE=HAILERS]The BAC also opens all the way upon startups......more air.

Hmmm, mine doesn't...Opens a little, maybe a 10% duty cycle, at start, and at idle with no loads...At low cruise speeds mine stays "active", the only time she really shuts down totally is at freeway cruising speeds above 3300 rpms or so...Even with the worst "abuse" I could put on it (idle, driving lights/headlights on, e-fan on) she was only doing about a 30%-35% duty cycle (about 8v at the ECU, which is the low end of the idle range voltages per FSM, with no loads)...

I could envision a scenario where guys that don't have their idles adjusted correctly (mechanically) would put a heck of a load on it...

NZConvertible

I think the next time some says "You don't need the BAC valve" or "You don't need the FPR solenoid", I'll just point them in the direction of this thread...

Kenteth

I think thats fair.

BTW, I had to fiddle with the FPR vac lines and ran out of vac line. I'll be fixing that tomorrow, as will I reinstall the BAC tomorrow.


I noticed yesturday that my aux ports were not opening. Another fault in my fully blown electronic aux ports. I tracked it down to the air pump. The motor had completely locked up and you could shake the unit and it rattled pretty good. The heat of being near the exhaust manifold must have did its number. I'm going to try mounting it somewhere near cold air in hopes to keep its life lasting longer than the 3 months it lasted this time.

SteveRanieri

This used to happen to me as well...and I have a rebuild. Weird thing though. I bleeded out the coolant for an unrelated problem and it seemed to have fixed the hot start issues too. It runs like brand new now...go figure.

seveninphilly

iTrader: (7)

Looking at your sig, how are you getting it to run without the omp on a '90?

Kenteth

sig says blocked omp, premix only. OMP isn't removed.

EDIT: And if I did remove the OMP, the car would still run, however only in limp mode.

Kurtis

i have the same warm start issue, i just put a new FPR and new injectors,new fuel pump,coils,spark plugs..... and i still have the damn problem...whats wrong?

WAYNE88N/A

It may just be an ECU bug, it happens to me every now and then, but doesn't seem to aggravate me like it does some of you guys. Not the hard to start part, just the weird low idle part...And I know all of my sensors are good, so I can't even begin to guess what could be wrong.

Maybe a vac leak somewhere that only rears its ugly head when the block and manifolds are totally hot and expanded???

Kurtis

im suppose to have some kind of performance chip and if it went out would it make my car be all weird?