dennis blackstone

i am wondering if any one has fixed the hotstart problem on there rex , we would all like hear , your resolve.

1987RX7guy

iTrader: (3)

Clean injectors usually help. Have yours checked out and clened if they are bad.

RXSevenSymphonies

iTrader: (2)

I thought I fixed mine by running Redline fuel injector cleaner through it, but that was just temporary until Redline ran out it seems, so I think my problem is either leaky injectors or just low compression, because I do have low compression.

Wanked_FC

iTrader: (1)

i had hot start issues, they went away after i removed all the emissions crap and teh rats nest, selonoids, etc.

Bukwild

yeah thats a easy fix. Just install a fuel pump relay cutoff switch. Cut the fuel to shut off the car and when you want to start it crank the engine and when it fires switch on the fuel and it will run like new. Also the fuel cut is a great anti-theft device. Better than any alarm.

xtremeskier97

That sounds like an easy 'bandaid' to me..not a fix. He may want to know how to actually FIX the problem...not just "patch it up".

My car suffers from this too....so I am watching this thread to see if there is something that I havent tried yet. I did get my injectors cleaned...though I KNOW I got SCREWED ROYALLY!!! ****** around here charged me over $100 to 'clean' my injectors...and they still leak. It wasnt until I came to this forum that I found out that I could have sent them to some place in OR or WA somewhere for like $12/piece.

VietFC

check your compression, and if necessary... rebuild.

dennis blackstone

yes i realy want to no how to solve this problem,not bandaid it, i have 30 thousand miles on the motor , injectors cleaned,90,90,90 compresion it runs beutiful, it started when i put my walboro,could it be fuel pressure, plus i have a safc,bnr turbo,i am stumped,i pray some one has any ideas .

Icemark

There are a couple of issues that can cause hot start flooding (if that is what you are complaining/asking about Dennis).

The #1 problem is leaking injectors. You would need to have them removed and professionally ultrasonicly cleaned. No pour in the tank crap will clean injectors that are bad enough to cause flooding.

#2 poor compression. Anything less than 90 PSI on each face means its time for a rebuild.

#3 damaged ECU and/or BAC. If the BAC or ECU was tested with a test light (as used by many truely incompetint mechanics/technicians) there could be a blown transistor in the ECU (more likely on S4 Turbo ECUs [N33X models]) This should be considered a last resort after the first two things have been checked. There are several write ups around the web for replacing the transistor, but the transistor itself is getting hard to find. Again, the first two things should be checked first.

Icemark

Your compression is very very low and ready for a rebuild.

xtremeskier97

What would be considered good compression?? I ask because once I get my engine running, Im going to get it compression tested.

KNONFS

iTrader: (14)

I wonder if the coolant temp sensor behind the water pump housing has anything to do with this issue; basically if the sensor goes bad, it riches the mixture.

I had the hot start issue on a good compresion engine, with fresh cleaned injectors, and no emissions (BAC was removed too). I replaced the stock ECU (series 5 NA) with a stand alone, and the problem went away. Either the ECU or the sensor was bad, however I sold the ecu and it has been working without a problem.

xtremeskier97

Hahahaha...Manasas, VA...home of Lorena Bobbit!! AAAAHHH!!!!

Sorry...had to. I used to live in Centreville, VA..just down the road from you. Graduated from Centreville High in '97.

What you say about the sensor/ECU could very well be the problem. 7s are notorious for their electrical problems.

KNONFS

iTrader: (14)

I wasn't aware of that unitll a couple of months ago

xtremeskier97

What!?! You live in a cave?!? It was HUGE news up there..and all around the country for that matter! LoL How long have you lived up there?

KNONFS

iTrader: (14)

Three years...

I knew about it, but didn't know it took place in Manassas, they even told me that the *member* was found in 66HWY

Icemark

Well there are actually a couple of other things (like that coolant temp sensor, and the hot start sensor on the intake manifold) that can cause the problem, but we can rule them out since he has such poor compression

Wanked_FC

iTrader: (1)

I was unaware that 90psi was considered 'terrible compression' and 'ready for rebuild'

I get bounces of around 95psi on my piston comp testor, but my idle pulls 460mmHg on my greddy gauge.

ddub

Not necessarily.

It all depends on what kind of tester is being used. For all you know 90 psi on that tester is 120 on another, etc. It's hard to tell with the just one tester and one car if it is entirely accurate. Best thing to do is get a KNOWN good compression/engine rx7 and test it on that then use that number as a benchmark.

Also, from my experience with multiple piston compression testers bounces of 90 doesn't necessarily mean its bad at all. All of the testers I've used bounce anywhere between 30 and 60 psi on every rx7 I've used or seen them used on. The problem with those was that the valve was letting out too much pressure before the rotor would turn into the next face. Additionally, with one of these testers I was getting in the 40's for bounces (all of them completely even), and then did a max test and got 105psi. Car ran perfectly, no starting (hotstart included) problems, nothing.

Before saying something like that I think you have to consider the fact that testers can be bias sometimes and you should check another car before assuming that is completely accurate.

However, I understand where you are coming from considering he has hotstart problems and that is a common problem with low compression engines or ones going out.

ddub

It's not.

My rule of thumb with compression is this.

Is the car running good? Is there no smoke? Does it start every time without problems (including hotstart problems)? Do you NOT have any flooding problems in general? Does it drive smoothly and has power stayed the same over time?

If you can answer yes to these then why worry about the actual compression numbers? Really compression is a tool used when your car is having PROBLEMS, why worry about it when your car is perfectly fine? Piston compression testers are not always complete accurate, and from what I've seen since many piston engines have much higher compression than rotaries the testers tend to be inaccurate (or it seems) down low. If you aren't having any problems then don't worry about it.

Also, since I have not had a tester yet that does the bounces at compressions that a lot of people say they're "supposed" to do, I go by these standards for testing. Test the bounces of compression for each face of the rotors. If all of them are equal then that's good enough. After that you can check max psi to get a better idea of the health of your engine, but the bounces being equal is all I care about for that portion.

Wanked_FC

iTrader: (1)

the bounces are even, im not worried.

Is the car running good? yes
Is there no smoke? yes
Does it start every time without problems (including hotstart problems)? yes
Do you NOT have any flooding problems in general? yes
Does it drive smoothly and has power stayed the same over time? yes

My car has never flooded, ever, even when its cold I start it for 30 seconds to move it.

ddub

Then don't worry about the bounces or max compression. Only worry about it when you have to start saying no to all of those

Icemark

Actually I consider anything under 95 PSI a candidate for rebuilding, but then as dDub says, I suppose it is possible for your test to be off or be inaccurate.

HAILERS

So how do you all square your figures with the fsm that says.......85psi @250 rpm?

xtremeskier97

Was kinda wondering the same thing.

and BTW...this that is supposed to be 2500rpm