Running rich

[Tom1987]

Hi all first time post, ill keep it to bullet points.
•2002 1.7 70k 4-2-1 mani sports cat tape ecu. Servicing good correct oil used etc (im a diag tech but not a ford tech, which is whats killing me not knowing whats wrong)
• recently lacking power feels like 10-20% gone, trying to stall when slowing down, but idle seems fine 850- 900ish rpm, hot or cold still the same, burning through fuel 95 or 99, 20 litres of either use to do 160miles now getting 80miles
• have snap on scanner no lights on dash but sometimes engine running rich fault code appears after 30 min town/motor way driving
• live data, o2 sensor sweeping up and down but not smooth and between .1- .7 not going up to .9? Also scanner reads flicking between open closed circuit whilst driving.
Icv flicking between open and closed whilst driving.
Maf at idle .9volts and changes smoothly with driving 4.7volts w.o.t. T.p reads roughly the same and smooth.
Coolant temp, air temp all read correctly. Short term fuel trim reads -15 at idle then will go to 0 when driving. Long term trim reads-25 then goes between -15 and -25 when driving. (Over fueling)
• ive changed maf sensor, coil pack, leads and plugs, o2 sensor, replaced wiring to o2 sensor (found white wire had .2 resistance) reset keep alive memory set idle and drive it. It seems every time i change something it behaves differently not sure if better but have got some power back after changing coil pack leads and plugs But cant see where else to turn except poss compression test?
If anyones got another route to take id be appreciative many thanks

 

[tuonokid]

Check the static cam timing. If it's not had a belt and tensioner kit recently the belt may have jumped and knocked the timing out.

 

[Tom1987]

Will do thanks

 

[Johnhneary]

Hi Tom I’m new on here, do you have any updates on this. What you have described is almost exactly the same as my 1999 1.7, I get a fault code for running rich after about 30 mins, it struggles to get through the Mot emissions test. I did lack power but like yours I replaced the coil pack leads and plugs. I also replaced the wirring to the o2 sensor, I also changed the o2 sensor, throttle position sensor and engine temperature sensor. I have the power back and the car runs really well again but is a bit jolly when combing of the throttle after the fault code has been logged. I’m not a diag tech but am a mechanic, I have also been thinking of doing a compression test but haven’t yet.

 

[Johnhneary]

Hi Tom I’m new on here, do you have any updates on this. What you have described is almost exactly the same as my 1999 1.7, I get a fault code for running rich after about 30 mins, it struggles to get through the Mot emissions test. I did lack power but like yours I replaced the coil pack leads and plugs. I also replaced the wirring to the o2 sensor, I also changed the o2 sensor, throttle position sensor and engine temperature sensor. I have the power back and the car runs really well again but is a bit jolly when combing of the throttle after the fault code has been logged. I’m not a diag tech but am a mechanic, I have also been thinking of doing a compression test but haven’t yet.

Sorry should say jolty when coming of the throttle only when the fault code has been logged, before that it runs smoothly

 

[Tom1987]

hi bud sorry havnt been on in a while, i just gave up after a while and just live with it. i did find a couple of thing which made it better and run abit nicer but im still getting on and off lack of power and running rich fault code. stuff i found.....
1. my maf sensor connector had a crack inside allowing a pin to be pushed out when plugged in, then when i remove the connector it goes back which hides the crack. but had also burnt that pin as it wasnt making a good connection. repaired that and better.
2. the wiring fault had killed another maf sensor, so replaced that and better
3. i had bosch coil pack and ht leads which i read isnt very good, so replace them with another brand and better.
4. fixed rocker cover leak to stop oil filling up no.4 spark plug, replaced spark plugs and gapped to 1.3mm, now much better.
5. replaced fuel relief valve on fuel rail as was sticking.

i was actually thinking of attacking it again this weekend to get to the bottom of it but depends how much time and energy i have. did you get any further with yours? or i will report back next week what i find.

 

[Waterboard]

I’m not sure but I’ll check the part numbers for the MAF sensor on older vehicles running TAPE against the later models.
I fell foul of this on a 20v Audi engine - subtle differences had big impacts

 

[Tom1987]

I’m not sure but I’ll check the part numbers for the MAF sensor on older vehicles running TAPE against the later models.
I fell foul of this on a 20v Audi engine - subtle differences had big impacts

everything i check i keep getting pointed back to the maf or tps. so that would make sense being slightly out of calibration with the ecu. i have still got the dive ecu so might put it back on and check the readings again.

 

[Tom1987]

would anyone happen to know?
1.throttle body position volts
2.maf sensor g/s
3.maf sensor volts
all at idle?

 

[caprixpack]

I can plug forscan into the millennium and see if I can get that info for you.

 

[caprixpack]

Both maf and throttle position sensor are new and genuine ford.

 

[benbunny]

The only time mine was running rich was when the coolant temp sensor was damaged. It still read ok and present but when the engine had warmed up by the gauge it still was sending a cold signal to the ECU. Replaced it and all was good.

Something to check.

 

[Tom1987]

you guys are legends thank you! my maf is reading the same average around 2.5g/s at idle and moves smoothly with throttle.
but my tps is .72v at idle, would that be enough to cause my problems?
my temp sensor is reading as it should but is there a way to see if it is stuck in warm up phase? and i have a new temp sensor any way as it was my next thing to replace. cherrs

 

[caprixpack]

you guys are legends thank you! my maf is reading the same average around 2.5g/s at idle and moves smoothly with throttle.
but my tps is .72v at idle, would that be enough to cause my problems?
my temp sensor is reading as it should but is there a way to see if it is stuck in warm up phase? and i have a new temp sensor any way as it was my next thing to replace. cherrs

When I get home from work I'll get on forscan again and see if there is any live data for the temp sensor.

 

[caprixpack]

Going through the live data there is nothing I can see to show if its stuck in a warm up phase. This is the data I could have live.

At ambient temperature the voltage was 3.19, as it warmed up the voltage dropped. Again its a new genuine ford sensor.

 

[GreenEyedPuma]

Tom, Hi, in response to the reply by "benbunny" re the Coolant Temperature Sensor, I was going to ask whether you had the older analogue dash (with the mechanical odometer), or the digital dash (with the LCD odometer).

However, I noticed that your original post mentioned "2002 1.7 70k 4-2-1 mani sports cat tape ecu.", so presumably you would have the digital dash, unless you're describing a newer PCM (ECU) you've installed in an older car?

The reason I ask about the dash (sorry to all who already know!) is that the analogue dash had the temperature gauge controlled directly by a temperature sensor / sender installed (I think) in the radiator, getting the gauge to tell the driver how hot it was! The digital dash gauges are all controlled by the PCM, so it runs the temperature gauge based on the Coolant Temperature Sensor, as well as operating the engine according to the temperature output of the CTS.

A failed, or very low reading CTS might have the PCM keep the engine on the "Cold Running Strategy" (the old people's "choke" ), but showing a low temperature gauge reading on a digital dash would likely give an indication of that. If you do have the old analogue dash, the separate radiator temperature sender might stop you knowing that a failing CTS is lying to the PCM about the actual engine temperature and keep it in the Cold Running Strategy. I'm no expert, but doesn't that involve richer running, as well as slightly higher idling speed and ignition advance (or is it retardation - I can't remember) and does it also stop the cat going into closed loop? Possibly all reasons for your problems, when the engine actually HAS got hot.

Sorry if you've already considered my suggestions about the dash type, radiator temperature sender versus Coolant Temperature Sensor and mine is all a bit of waffle! If so, hopefully this might still give some further insight for anybody suffering similar problems who've Googled and found this thread and it might be of help to them.

p.s. If you or anybody else replaces the Coolant Temperature Sensor, under the ignition coil pack, it is MUCH easier if you remove the battery and battery box! That gives you loads of room for your hand, forearm and elbow, to unscrew and reinstall a replacement from below. I've done it twice and couldn't understand why it was so difficult to install the second time, until I remembered about the battery..... Oh well, you live and forget!!!

 

[Tom1987]

Going through the live data there is nothing I can see to show if its stuck in a warm up phase. This is the data I could have live.
View attachment 10650
At ambient temperature the voltage was 3.19, as it warmed up the voltage dropped. Again its a new genuine ford sensor.
View attachment 10651

these are great buddy i do appreciate it.

 

[Tom1987]

Tom, Hi, in response to the reply by "benbunny" re the Coolant Temperature Sensor, I was going to ask whether you had the older analogue dash (with the mechanical odometer), or the digital dash (with the LCD odometer).

However, I noticed that your original post mentioned "2002 1.7 70k 4-2-1 mani sports cat tape ecu.", so presumably you would have the digital dash, unless you're describing a newer PCM (ECU) you've installed in an older car?

The reason I ask about the dash (sorry to all who already know!) is that the analogue dash had the temperature gauge controlled directly by a temperature sensor / sender installed (I think) in the radiator, getting the gauge to tell the driver how hot it was! The digital dash gauges are all controlled by the PCM, so it runs the temperature gauge based on the Coolant Temperature Sensor, as well as operating the engine according to the temperature output of the CTS.

A failed, or very low reading CTS might have the PCM keep the engine on the "Cold Running Strategy" (the old people's "choke" ), but showing a low temperature gauge reading on a digital dash would likely give an indication of that. If you do have the old analogue dash, the separate radiator temperature sender might stop you knowing that a failing CTS is lying to the PCM about the actual engine temperature and keep it in the Cold Running Strategy. I'm no expert, but doesn't that involve richer running, as well as slightly higher idling speed and ignition advance (or is it retardation - I can't remember) and does it also stop the cat going into closed loop? Possibly all reasons for your problems, when the engine actually HAS got hot.

Sorry if you've already considered my suggestions about the dash type, radiator temperature sender versus Coolant Temperature Sensor and mine is all a bit of waffle! If so, hopefully this might still give some further insight for anybody suffering similar problems who've Googled and found this thread and it might be of help to them.

p.s. If you or anybody else replaces the Coolant Temperature Sensor, under the ignition coil pack, it is MUCH easier if you remove the battery and battery box! That gives you loads of room for your hand, forearm and elbow, to unscrew and reinstall a replacement from below. I've done it twice and couldn't understand why it was so difficult to install the second time, until I remembered about the battery..... Oh well, you live and forget!!!

hi buddy yeah digi dash with tape pcm, i have been down many rabbit holes searching for this fault thats hiding from me, i will find the problem i just don't get much time to actually dig into to it (hence its been on going for a while) but ive decided its getting fixed now, so will hopefully have an answer this week
and im repairing the bubbly rear arches as a treat lol

 

[Wild E. Coyote]

How is your lambda probe? I would look into the raw voltage. IIRC, at 0.5V it should be lambda=1. Lower voltage would give lean mixture (lambda >1), and over 0.5 it would give rich conditions (lambda <1). As you can see these are very low voltage outputs and say your contact is not ideal and you have some additional resistance, it would drop the voltage below stochiometric 0.5V treshold, but still be perfectly within the operating lambda probe output range (hence no DTC). But the PCM would read lean conditions and adjust accordingally (i.e. enrich the mixture) to overcome that and in fact the engine would run rich. SInce you have TAPE PCM it has no second lambda to check everything once again after the catalyst.
So, I would look into lambda raw signal at pins and measure he voltage BEFORE it reaches the connector and PCM.

 

[Tom1987]

i think ive got to the bottom of my issues, but first just wana double check im resetting the pcm learn values right.
is it disconnect the batt for 1 hour,
then let it idle with all the electric loads on untill warm.
then increase to 1200rpm for 2mins.
then drive it as you would?
i right up what found to fix it
cheers