weird problem

[SupraBro]

Ok, so i have a 88 supra 7mgte and every since i built the car about a year ago i have had this problem. Here is my day, i start the car up in the morning and it runs fine. Once it has warmed up and i turn it off, it has problems trying to start. It misses bad and its hard to rev, but if i keep reving it it will go away, sometimes it takes awhile. But if i let it cool off it will start right up??? So lost on this problem and it has been getting worse week by week. any ideas would be great!!!

thanks,
brandon

 

[89supracrazy]

Did you check your engine codes?

 

[D.J.T.]

Did you check your engine codes?

I have the same problem. only engine code i get is 52. Which is Knock Sensor.

 

[ForcedTorque]

I hate to be the dick that runs in here to say "Search". But, I don't know the answer, and it is a common problem. The answer is around here somewhere.

 

[nsngarage]

I'd be willing to bet you have injectors that are going bad.. my car ran GREAT until it got hot enough to short an injector out.. found the bad injector by unplugging them one by one to see which one didn't cause a change.. replaced it, and i was good to go..

just another thought.. check your fuel pressure when you try to restart it and it's giving you problems.. might have something sucking up and clogging a bit... just my .02

 

[D.J.T.]

I hate to be the dick that runs in here to say "Search". But, I don't know the answer, and it is a common problem. The answer is around here somewhere.

I've searched & found threads with no answers & i've posted in those threads & NOTHING.

 

[mkiiichip]

This is one of the extremely common 7m issues, and it is commonly found to be boiled fuel in the rail. to check if this may be the cause;

When you are going to re-start the vehicle, and you are sure the heat soak will cause the car to run crappily, turn on the ignition (without starting the car) and jump FP and B+, for a min. Then remove the jumper and start as normal. If the car starts and runs as normal, then there was boiled fuel in the rail.

How do you fix this? IDK. There is already a system to prevent this, so that may be a start. But a properly functioning "hot start pressure up" system is not always enough.

At least thats what i found on my 7m.

 

[jetjock]

This symptom is typically caused by a loss of rest pressure. Since vapor can't form in the rail with it present that's where I'd begin looking.

 

[JStoked]

There was just a post on this prob about a month ago or so. Check your vsv valves to make sure they are hooked up ( i think that's what they are called) there are two under the intake one is for the egr valve and the other is for the fuel pressure regulator. They let the the boiling fuel bleed off while sitting. i believe that's right.

---------- Post added at 09:50 PM ---------- Previous post was at 09:48 PM ----------

And listen to jj. He knows all.

 

[jetjock]

Well, not all. Besides, chip called it and lacking a gage his suggestion of jumping the fuel pump on to confirm is a good one. Most fuel injected engines can be a bitch to hot start after 30-60 minutes if rest pressure (Toyota calls it residual pressure but I prefer the Bosch term) is lost. Raising the fuel's boiling point to combat vapor formation is the sole reason behind maintaining supply side pressure after shutdown. It's the same principle used in the cooling system.

 

[SupraBro]

thanks for the help guys!!! well dont bash on me to hard but i have suprasport block off's and no egr on a non jdm ecu....would this cause the problem??? I tried to search this problem but all the other threads were diffrant for the most part. I will look into the ideas from above post and once again thank you guys so much for the help!!

 

[89supracrazy]

I have been looking at this for sometime. I would like to do away with the cold start injector. If I am right all you have to do is put a 12 volt time relay on the fc which is the green wire and and let it make with a good frame ground. Of course you will need the black with orange strip igsw to power the relay. This would fix the heat soak problem because it would flush the hot fuel out of the rail and back to the tank.

http://www.cygnusx1.net/Supra/Library/TEWD/MK3/manual.aspx?S=Main&P=49

 

[SupraBro]

Its bad today!!! About 15 min into driving it started to miss bad??? It is driving me crazy!! It is now starting to do it while i drive, before it would only do it on start up when it is hot

 

[D.J.T.]

Did you check your spark plug gaps? to install spark plugs use a piece of vaccum hose.. slowly put it down the valley & twist & after a few just pull the hose & you'll be able to tighten it with a socket.

 

[89supracrazy]

What part of tennesse are you from? Just curious. You might be close to where I live.

 

[Compton74]

i was also told that running more water then coolant causes things to become much hotter, due to the boiling point of coolant and water being different, thus boiling the fuel in the rail. So are you running straight coolant, or straight water, or a 50/50 mix?

 

[SupraBro]

It's a 50/50...the new spark plugs a gapped right...thanks for your help!

---------- Post added at 02:00 PM ---------- Previous post was at 01:59 PM ----------

What part of tennesse are you from? Just curious. You might be close to where I live.

Middle Tennessee....Nashville area..where are you?

 

[89supracrazy]

I live around the duffield virginia area.