leaning out issues please help!

[NewGen]

My cars running really lean all the time right now. It's ideling around 16 on my wideband. When it climbs into boost it'll kinda fall on its face then pick back up and run really strong. I've replaced my fuel pump, fuel pressure regulator and my fuel pulsation dampiner. Another thing thats happening is the coolant guage is moving up and down with the rpm's of the car. It's not throwing any codes at all. Anyone have any idea what it could be?

thanks

matt

 

[Mrbaboon]

Questions:

How far up/down is your coolant gauge moving?

Have you checked your timing?

Have you checked your fuel pressure?

Personally it sounds like it might be a timing issue, but really it could be a lot of things.

 

[SUPERIUM]

Well for the coolant jumping up and down it sounds like your temp sending unit is shitting out on you.
For running lean have you replaced your injectors? I would atleast take them out and have them cleaned and flow balanced. Replace the fuel filter if you havent already as well.

 

[tubbie]

Check the vacuum line to the pressure regulator.

 

[NewGen]

Questions:

How far up/down is your coolant gauge moving?

Have you checked your timing?

Have you checked your fuel pressure?

Personally it sounds like it might be a timing issue, but really it could be a lot of things.

Coolant guage will move way above the hot zone out of the guage itself. I plan on checking the timing. Does anyone know how to disengage the electronic advance? I havnt checked my fuel pressure i'm going to do that soon as well.


I havnt cleaned the injectors. I just put the engine back in the car a few weeks ago so if all else fails i'll put the injectors and check those next.

I just replaced the vacuum line to the regulator today.


I put a used fuel pressure regulator in it yesterday thinking that could of been the problem. Before replaced it would run rich sometimes and other times it would run lean it just kinda depended on the day. I thought that should eliminate the pump and the filter. I dont think its the fuel system just because it was running rich at one point. The funny part is sometimes it will run just fine and other times it will just run like crap thats why i'm so confused.

 

[Mrbaboon]

Does anyone know how to disengage the electronic advance?

Jumper that shit. T + E1 = Success!

Check the timing asap and get back.

Coolant gauge will move way above the hot zone out of the gauge itself.

Very bad. I fear for your head gaskets future. (unless you're lucky as hell and it's the sending unit, but I doubt it).

Before replaced it would run rich sometimes and other times it would run lean it just kinda depended on the day.

excuse my nubness in this department, are you running your stock O2 sensor as well as your wideband?

If so, have you checked the O2 sensor?

..and on the injectors, I don't think your issue lies there, you would have some crazy issues running all the time, I think.

 

[NewGen]

Jumper that shit. T + E1 = Success!

Check the timing asap and get back.




Very bad. I fear for your head gaskets future. (unless you're lucky as hell and it's the sending unit, but I doubt it).



excuse my nubness in this department, are you running your stock O2 sensor as well as your wideband?

If so, have you checked the O2 sensor?

..and on the injectors, I don't think your issue lies there, you would have some crazy issues running all the time, I think.

sorry im alittle new to the jumping thing so ill pm you and get more info on that. It doesnt seem like its gettin hot when it goes above that zone and the engines been studed and has a mhg but its always a possibilty i'm going to check the compression so i'll know hopefully for sure. Another guy i pmed on supra forums said it could be the water pump or the fan? I welded a bung into the top of my downpipe for my wide band. My stock o2 sensor is still on my turbo elbow is that bad? I have not checked my 02 senors should i just go ahead and replace it? I didnt think it was my injectors. I didnt go home tonight be as soon as i do get home i will check the timing and let you guys know whats up.

thanks again

matt

 

[NewGen]

ok.. I wasnt getting any vacuum to the fuel pressure regulator so i fixed that. Checked my timing. It was fine. We checked for boost leaks and i had a slight one so i fixed it. Ran the car for awhile made the mistake of leaving the boost controller turned it up boosted up to about 13 psi and hit fuel cut but was rich pretty much the hole time while it was in boost. Then out of no where it started having issues again... I'm still getting plenty of vacuum to the fpr and i'm not throwing any codes. Is there any way if my coolant sending unit was bad that it would tell my ecu to add more air and less fuel to help cool it down? Thats where i was going to start next and move onto injectors if that didnt fix it.

 

[Poodles]

you'll read lean if you're missfiring as well...

higher RPMs = faster moving water pump...

could be a bad waterpump, but you also boost at higher RPMs which would cause exhaust gasses to be forced into the coolant overheating it...

do the coolant exhaust gas tester, do a compression test, and pull the plugs and check them (gotta pull em anyway to do the compression test)...

 

[slidebabyslide]

you'll read lean if you're missfiring as well...

higher RPMs = faster moving water pump...

could be a bad waterpump, but you also boost at higher RPMs which would cause exhaust gasses to be forced into the coolant overheating it...

do the coolant exhaust gas tester, do a compression test, and pull the plugs and check them (gotta pull em anyway to do the compression test)...

WHY DO YOU HAVE TO SCARE PEOPLE.:3d_frown: .......LOL.
I was thinking the same thing, but i hope it's nothing bad with your car.
When timing is to + they tend to overheat.

 

[Poodles]

true dat...

but the first thing he should do is STOP DRIVING IT.

diagnose the problem and go from there, as driving it in that kind of condition is just asking for a warped head, BHG, and eventual rodnock from contaminated oil...

 

[NewGen]

you'll read lean if you're missfiring as well...

higher RPMs = faster moving water pump...

could be a bad waterpump, but you also boost at higher RPMs which would cause exhaust gasses to be forced into the coolant overheating it...

do the coolant exhaust gas tester, do a compression test, and pull the plugs and check them (gotta pull em anyway to do the compression test)...

Ya its missfiring at idle. I did a compression test resently and it was fine. I changed my plugs 2 days ago they were very black which means they were running really rich. which it will run rich sometimes as well as running lean. I'm going to check the coolant exhaust gas tester today.

 

[NewGen]

ive pretty much come to the conclusion its the sending unit. I'm ordering one tomarrow. I think it will take are of my leaning issue also.

 

[NewGen]

well... I replaced it tonight. It runs really well untill i run it at wide open throttle and let off real hard. Then it starts to lean out and doesnt want to idle properly. Could this be caused by my bov? Its the stock ct26

 

[Poodles]

all the way off throttle = no fuel = engine braking = full lean

 

[NewGen]

k but its still lean at idle and then after a few minutes runs rich on my wide band 10.0 and then tries to cut out and my coolant guage is still going blastic up and down based on rpm.

 

[Poodles]

wtf....kinda stumped here...

 

[NewGen]

ya.. Same here.. Do the ecu's in these cars have issues sometimes? Any chance it could be the tps sensor?

 

[Aspec]

k but its still lean at idle and then after a few minutes runs rich on my wide band 10.0 and then tries to cut out and my coolant guage is still going blastic up and down based on rpm.

1st - There are two coolant temp sensors. One operates only your gauge and has no effect on driveability. The other provides a signal to the EFI system (TCCS) and the ECM uses it as a reference to control A/F. Make sure you did not mix them up when you did your install.

2nd - Did you do a block test yet for combustion gasses in you coolant?