4.0 ohv troubleshooting help needed

[hotrod66]

Hi, after searching for a long time I finally try my chance here.

I have a 4.0 V6 OHV in my Ford taunus coupé. The engine comes from a 93 ford explorer first gen. It's now mated to a manual gearbox and still uses EECIV management.

Here is the problem: I never had the explorer on the road neither started it before removing the engine to install it in the Taunus. Since that, the engine never ran well. It start fines, drives fine but if I want the original power I need to cut out the ignition with the key and switch it on back and for around 1 minute I can put full throttle and have the full power. After this time, the engine become again a smooth but powerless engine. I tested the exhaust gaz and I have too many oxygen (O2) good Co, not enough CO2 and too much HC coming out the exhaust:
at idle:
O2: between 4 to 7.5%
CO: between 0.45 to 0.60%
CO2: between 9.5 to 12.5%
HC: between 500 to 750!!!

at full throttle:
O2: between 15 to 15.5%
CO: between 0.15 to 0.30%
CO2: between 2.5 to 3.5%
HC: between 900 to 1900!!!

I was thinking about a fuel pressure regulator problem but I have changed it and it's the same. Now I think about Lambda sensors or manifold temperature sensor...

Do you have any idea or did it happen to somebody here?

thanks for you help and ideas

 

[natenkiki2004]

Temp sensors (ECT & IAT) don't usually cause huge drivability problems but rather hard starting, at least that's what seems to be the trend in our Explorers.

Start with cleaning the MAF and verify that the TPS is good. I was thinking your O2 sensor but if it's dumping more fuel in (high HC) then it's probably not reading airflow right.

 

[coco944x4s]

If engine and computer came from an automatic explorer, you might need to try a manual computer. I have been told in the past by others that doing a manual swap on a explorer from 93 and up that those model computers are just smart enough to know the automatic isn't there. This may not be true for all 93's but I know my 94 has dual oxygen sensors and camshaft synchronizer. My wife's 92 has neither of those so logic dictates my 94 is "smarter".

 

[jester1023]

I'm not going to be able to give any advice on your problem, but that's one cool little car...I want one.

 

[hotrod66]

I'm not going to be able to give any advice on your problem, but that's one cool little car...I want one.

Ah, Ah! you will hardly find one in USA... I am in France in Europe. It's a german Ford model for Europe market. It's known as Cortina MK3 in UK.



Thanks for other comments, I have ordered the Lambda O2 sensors (there are 2, one on each downpipes), I'll let you know if it is the cause of the problem.

The TPS is working, I have checked it ans the MAF looks to work too, but I'll check if it's clean.

If you have some others suggestions, don't hesitate

 

[natenkiki2004]

Do clean the MAF, these designs typically need cleaning quite often. Some members clean it every time they change oil.

 

[hotrod66]

I'll try to clean the MAF and see what happen. What do you think is the best way to clean it?
It's a hot wire if I'm not wrong.

 

[natenkiki2004]

It is a hot wire but just unplug the sensor, remove it from the housing and spray it down with a cleaner. If you can't get MAF Cleaner (it's expensive anyway), something like brake cleaner should work. I've heard that there's a light lubricant in electrical cleaner so I wouldn't use that.

 

[hotrod66]

hi everybody! new MAF ordered and installed and the car is now a monster! Thanks for your help

 

[natenkiki2004]

We're going to need a video to prove it, preferably with some WOT runs and a burnout or two.