bogs down when gassed, 351efi gt-40

[maverickconner]

this is getting to me, I thought it was the timing, but now I do not know what it is.... It idles perfect runs good for about 30 seconds, then if you gas it, it sounds like it is getting no gas or no air...

also, after it runs for a while, it is hard to start....

 

[Socal Tom]

First pull the codes
Check your fuel pressure
What computer are you running? injectors, MAF?

Odd are you have an sensor that's out, or your not getting fuel to the injectors.
Tom

 

[maverickconner]

I am actually looking for a cross reference for my MAS, I bought it on ebay and hope the guy did not hose me..... any help would be great,,,E07F-12B579-A1B-AFH55-05 are all the numbers on the list.....

computer is an A3M,,, stock injectors 19Lbs

 

[Socal Tom]

Yep,
Pull the codes, If you don't get any unexpected errors, I'd try unplugging the MAF and see if anything changes.
Tom

 

[oh2bnok]

If you have an inline fuel filter I would also check that it could be restricing your gas flow.

 

[maverickconner]

I do have an inline filter, I will check that next.


Here are the codes that I am getting when key is on,,,not running

Neutral saftey 67
TAD failure 82
TAB failure 83
canister purge 85
EEC not recognizing fuel pump as being on

When I start the Bronco...

I get a pause then a continuous light on... no blinks??

 

[Socal Tom]

It won't let you get KOER codes unless the NSS says that it's in nuetral. You should hook up the FPM and hook up an NSS signal.

Personally I suspect the MAF, or fuel supply. When it starts initially it uses preset defaults for the sensors, once it's warmed up it starts reading sensors. In your case it's fine until it starts to read the sensor feedback, so I tend to think it's probably not fuel, but I can't be positive without testing it.

If it's getting inaccurate MAF readings, then I suspect it will act like you say. if you disconnect it, it will try to operate in LIMP mode and if it works better like that I would do the tests in the Probst book on the MAF.
Tom
I still recommend hooking up the FPM and giving it a NSS signal. I'm not positive, but for an auto tranny computer I think you just ground the NSS signal. Ryan's site should have the info.
Tom

 

[maverickconner]

just got back from Oriely's , know a guy up there. Says my mass air sensor is off of a 4.0L 95' ranger pickup.......ARGGGGG I have been hosed by Ebay.....

Gee, think that may make it run a little funny.....?

 

[Socal Tom]

I think you found the main culprit.
Tom

 

[SaddleUp]

Could be that MAF meter. I would still try to get the KOER codes and then do a cylinder balance test. (Lightly tap the pedal within 2 minutes of running the KOER codes) I had an annoying problem with mine that I also thought was timing. The first thing that turned up when I was running the KOER codes was tha ACT sensor being out of limits. It didn't come up with the KOEO codes though. I replaced the ACT sensor and it seems to have taken care of my problem.

 

[maverickconner]

OK, I got the running codes,,,

first was 12- cannot control idle
second was 41 no HEGO switching on right,,,lean right
third was 91 no HEGO swithch on left,, lean left


what is going on with this???? could this be because of the mass air issue???

 

[SaddleUp]

OK, I got the running codes,,,

first was 12- cannot control idle
second was 41 no HEGO switching on right,,,lean right
third was 91 no HEGO swithch on left,, lean left


what is going on with this???? could this be because of the mass air issue???

On #12 I would hold off on diagnosing it specifically since it will probably go away once you get it running right. On the others I would get the right MAF meter in it first and see if they still come up. You might try unplugging the meter as mentioned above and see if that makes it change. It will probably run better in limp mode until the right meter is in there.

 

[maverickconner]

OK,
I unpluged the MAF and tried it in limp mode, it runs about the same, except it does not want to stay started when you crank it. It will stay started after you give it a little gas though. So I guess this means that the 4.0 MAF is not compatable with the 5.0 ,,,lol

 

[heylouie00]

Also, try fuel related items like pumps, filters, switches, etc.

I had a 6-port electric switch give me all kinds of problems...no real codes, but It acted like you are describing...I suspected MAF, TPS, etc. then I started troubleshooting my fuel circuit & traced it back to the switch. I bypassed the selector switch & it fixed the problem.

Coincidentally at one point it did give me the HEGO codes...

HTH

--Craig

 

[SaddleUp]

OK,
I unpluged the MAF and tried it in limp mode, it runs about the same, except it does not want to stay started when you crank it. It will stay started after you give it a little gas though. So I guess this means that the 4.0 MAF is not compatable with the 5.0 ,,,lol

Is the timing off? I.E. Did you play with the timing to try to get it to run right? If so then that could be effecting how it starts up.

 

[maverickconner]

I just did the timing this morning, it advanced to tdc just fine. The fuel pump is brand new, but I am going to replace the mass air first, then try to see if it is the pump or filter....

 

[Bronco Ben]

i just replaced the fuel pump on my 89 dokota (with one off a 91 Mustang GT I might add lol) and it fixed my surgeing, poping back thru the intake, not wanting to accelerate problems. I'd say its either fuel pressure related from either bad filter or pinched line when the tank was re-installed??? or bad fuel pump. Sounds like a fuel restriction to me...good luck! hope you get er fixed soon
Ben

 

[Socal Tom]

OK, I got the running codes,,,

first was 12- cannot control idle
second was 41 no HEGO switching on right,,,lean right
third was 91 no HEGO swithch on left,, lean left


what is going on with this???? could this be because of the mass air issue???

Cannot control idle probably means that you have the idle set too fast. 41 and 91 can be from a lot of things, the first thing I would do is unplug one, and see if you got them plugged into the correct side. I think you can also get those from having the HEGO too far from the manifold, like after a set of long tube headers.
Tom

 

[maverickconner]

OK, here is what I did, it was a combination of things.

1st- switched the hego wires
2nd- put a new "yes, brand new" 93' mustang 70mm maf on

This did a lot better, but not when I really got on it, but it did idle better and rev faster.....

3rd, replaced the fuel filter,,,,while doing this noticed crap pouring out,,,nice. One additive of fuel treatment, one additive of fuel injection cleaner,,,,,and the need for a new tank,,, replaced the fuel filter, and I was doing burnouts in 2nd gear,,,, YEHAW......


Thank you everyone,
Patrick

 

[Socal Tom]

Nice,
Good work.
Tom