running out of ideas

[SB98UKexplorer]

im in the process of still trying to sort out my lean power above 3000 rpm

so far i have:

checked air hoses for leaks
checked the vacum on plenum chamber valve and movement
replaced fuel filter
replaced injectors
new fuel pump, uprated to 255 lph
new 10mm leads and new spark plugs
ran 2 bottles of redex
decats
tightend throttle cable
swapped over 2 mafs
new o2 sensors
swapped over 2 throttle sensors

no engine light or codes
engine idles perfectly
no missfires inc underload
engine oil clean brown with hint of gold.

temprature guage never read center, just near

there maybe afew other things iv done but im finding myself come to a dead end..

 

[Howard]

An odd one, but some things you can check. Crankcase breather for leaks, PCM for programming. Also the upper intake manifold, The little vacuum module that is supposed to change the airflow over 3000 rpm. At the rear of the manifold.

 

[chrisquelch]

hi Steve i know you have bigger capacity fuel pump but have you checked the fuel pressure when running engine it could be pressure relief valve

 

[2000StreetRod]

Variable Induction System

An odd one, but some things you can check. Crankcase breather for leaks, PCM for programming. Also the upper intake manifold, The little vacuum module that is supposed to change the airflow over 3000 rpm. At the rear of the manifold.

Excellent suggestion! The intake runner length is supposed to start changing at 3,000 rpm and be complete at 3,500 rpm. It is PCM controlled but vacuum actuated. There is a vacuum reservoir between the upper and lower manifolds. Make sure it is connected and the vacuum hose is in good condition. As Howard said, check the actuator. Several members have found that the actuator rod was disconnected from engine vibration. There is also a solenoid/vacuum valve controlled by the PCM that activates the vacuum motor. Check the vacuum hose from the solenoid to the vacuum motor.

 

[SB98UKexplorer]

hi Steve i know you have bigger capacity fuel pump but have you checked the fuel pressure when running engine it could be pressure relief valve

hi chriss are you refering to the fuel regulator with the vacum tube that sits on it jus near the throttle body?

 

[DuncanOfEngland]

Lean mixture

Steve,

Lean mixture is caused by too much air or not enough fuel. I see that you have a bigger throttle body, so why not fit higher flow fuel injectors?

Duncan

 

[chrisquelch]

hi Steve i was suggesting connecting a test gauge to the fuel line to see if it holds good pressure at high revs. but as Duncan says its not enough fuel or to much air. you could refit the old throttle body to see if that cures it.

 

[SB98UKexplorer]

has any one got a ecu with box code BML1, iv froze the ecu program when i read it with my sniperforce program, car will not start now.

 

[chrisquelch]

pcm

hi steve i have 1999ex i am starting to dismantle tomorrow i dont know what the code on pcm is at the momment will know later today or tomorrow cheers chris

 

[chrisquelch]

pcm

hi steve sorry for the delay i now have a pcm with the code you wanted pm me if you still need one cheers chris

 

[regorsmith]

Hi Steve,

I've read your post with interest as i've had a similar problem with my ex also.
i couldn't get any power over three thousand rpm and it would splutter up to 3500 rpm, just.
The lower rev ranges were fine, but again, the kick down was powerless.
I did all the usual suspects, plug and leads and air filter.
No change. Checked the resistance on the EGR valve vacuum solenoid, and that was fine too. Had the EGR valve off and that was fine too.
If the cars at idle and you want to check the solenoid vacuum, just behind the IAC valve, then lift off the plastic cap and there should be a little spout that blows air out the top. put your finger over the hole, the EGR will lose vacuum and the engine will die. if this doesn't happen the your EGR valve solenoid vacuum actuator is probably shot.
Also the other suspect was the DPFE sensor (Differential Pressure Exhaust Sensor). This is also known as the EGR position sensor, and is the black plastic box, aluminum on the earlier ex's, on the right hand side of the engine, with two tubes pointing downwards and connected to the EGR pipe, which connects to the EGR valve at the front of the engine, by a small rubber tube and a slightly larger bore rubber tube. Both about 4" long. If the sensor can not read the upstream and downstream exhaust pressure difference via this sensor then the PCM does not know what signal to send to the EGR vacuum actuator solenoid. It then defaults back to open position, idle, to keep the emissions low, but does not close the EGR valve vacuum off when the engine is revving hard. The result is more exhaust gas's in the plenum chamber than can be combusted in the combustion chamber. Loss of power is the result.
I chased this around for ages until it finally dawned on me that the DPFE sensor was my problem.
I changed it today, thanks chris Q for the DPFE Sensor, and the Ex is running perfectly.
The code that it threw up was P1401 - EGR flow insufficient.

Taking the battery off for 30 minutes might reset your PCM. That's what my local Ford dealers suggested to lose any codes if you don't have a reader.
It should just default back back to learning mode.

Hope that this helps you get going again...

Roger

 

[SB98UKexplorer]

cheers for that info, on the first days of working on it when we picked it up, the egr sensor (black box) had a hole burnt through the top, replaced that but had no error codes, iv only ever seen one related to lean power when the light came on after booting it around, it showed up as lean bank 1 but cleared soon after, its deffently electrical sensor problem, but i will have ago at testing out the egr system.

 

[regorsmith]

Your welcome,
Hope you get it sorted soon..