Ford 4.6 twin cam v8 engine woes.

Ford 4.6 twin cam v8 engine woes.

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happy fish

Original Poster:

58 posts

194 months

Saturday 12th March 2022
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Hi I have a Ford 4.6 twin cam v8 in my hot rod , one bank of the engine is running lean and on the exhaust manifolds is running at the correct temperature, the other bank is running rich and the temperature on the manifolds is cool very cool.
It has an MBE ecu and jenvey throttle bodies I have had trouble finding someone who can set this up .
Worried I may do damage to the engine so have only been letting the engine idle since I discovered this , any help or info much appreciated.

Boosted LS1

21,198 posts

267 months

Saturday 12th March 2022
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Was it ok before or is this something that happened since you added the mbe and wiring harnes? Is it a fresh installation that's never run?

stevieturbo

17,535 posts

254 months

Saturday 12th March 2022
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happy fish said:
Hi I have a Ford 4.6 twin cam v8 in my hot rod , one bank of the engine is running lean and on the exhaust manifolds is running at the correct temperature, the other bank is running rich and the temperature on the manifolds is cool very cool.
It has an MBE ecu and jenvey throttle bodies I have had trouble finding someone who can set this up .
Worried I may do damage to the engine so have only been letting the engine idle since I discovered this , any help or info much appreciated.
How are you determining one bank is lean ? and likewise one is rich ? What are the actual AFR's on each side, and are you getting at least a spark on all cylinders ?

Has this ever ran correctly ?

happy fish

Original Poster:

58 posts

194 months

Saturday 12th March 2022
quotequote all
When I start the car up and let it idle for approx 5 mins I have a thermal thermometer, right bank approx 22 c left bank about 80 c .
When I bought the car it had not run for maybe approximately a year after doing the usual safety checks started car and it ran ok but very rich . I decided to take it to a rolling road tuner so they could map the car and get it running cleaner alas they proved to be useless and I’m now in the position that the car runs like this .
When I purchased the car it was difficult to drive as it was backfiring via the exhaust and occasionally through the trumpets . The people I gave the car to tune assured me they would get it running sweetly, when I took it out for its first test it ran ok but backfired a lot , that’s when I discovered the spark plugs .
What I really need is someone who understands the mbe ecu and how to map it

stevieturbo

17,535 posts

254 months

Saturday 12th March 2022
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So it has never run right ?

Discovered what with the spark plugs ?

Is the engine even healthy ?

Why not contact MBE and ask them for a recommended tuner ?

Really you're shooting in the dark.

It has never run correctly, it could be a mechanical issue ( less likely, but valve timing perhaps ? ), or more likely an ecu setup or wiring issue.

It shouldn't be too difficult to get a wiring diagram and manually check the thing is even wired correctly. Could be firing order messed up, coil wiring incorrect, etc etc.
Do basic stuff first, and stop running it until some of this has been confirmed or you risk causing harm.

IMO thinking it needs mapped first.....no, it needs basics covered first unless you want to pay someone to go through all the wiring etc first before attempting to tune it.

Although at least communicating with the ecu initially, might reveal something badly wrong with the base setup too. If you are unable to do this, then manually check wiring etc.

Edited by stevieturbo on Saturday 12th March 22:47

Boosted LS1

21,198 posts

267 months

Sunday 13th March 2022
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In addition to what Stevie has said I'd also check fuel pressure is equal on both banks.

stevieturbo

17,535 posts

254 months

Sunday 13th March 2022
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And to add.


Have you even any reason to think it should run ?

Was it sold to you because the previous owner had problems ? You have never had any evidence that it has actually ran correctly ? Who supplied the ecu or loom ?

You say you took it to someone who assured you they would get it to run.....who were they ? and what was that outcome, as clearly it is not running ? Why did you believe they would get it to run ? And why did they not ?

History can reveal a lot. Surely they gave you some answers ?

If the engine is mechanically healthy, it should not be that difficult to resolve. Unless there are a plethora of problems created by whoever built/wired it in the first place.

Might be easier in some cases to start from scratch

happy fish

Original Poster:

58 posts

194 months

Sunday 13th March 2022
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Thanks for the response
Yes I’m going to phone mbe on Monday and see if they can recommend someone.
I do believe the engine is healthy and and I have checked the fuel system .It has a high and a low fuel pump with a plenum chamber , I have fitted a fuel pressure gauge to the union where it integrates . Mbe supply a diagram for this.
At the moment I don’t want to name the firm who I gave the car to but once I have resolved the situation and get the car running right I may name and shame.
I have phoned around and asked for recommendations, when it comes to mbe most firms don’t want to know .

Paul Mann2

4 posts

32 months

Sunday 13th March 2022
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happy fish said:
When I start the car up and let it idle for approx 5 mins I have a thermal thermometer, right bank approx 22 c left bank about 80 c .
Do you mean you are checking the exhaust manifolds with an infra-red thermometer? If so then both 22C and 80C seem unfeasibly low if you have cylinders that are actualy firing.

stevieturbo

17,535 posts

254 months

Sunday 13th March 2022
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happy fish said:
Thanks for the response

At the moment I don’t want to name the firm who I gave the car to but once I have resolved the situation and get the car running right I may name and shame.
I have phoned around and asked for recommendations, when it comes to mbe most firms don’t want to know .
Even without names, what was their outcome ? Their explanation as to the problems and why they could not do anything, or even suggest anything ?
I'm not saying it was their fault, but some sort of explanation would help, along with any of their findings.
Did anything change from before and after ?

And TBH, after looking at MBE's software years ago as I nearly had to work at a car with one, I probably wouldn't want to know either. Terrible software.

Sometimes as said, the best recommendation is to start from scratch, with known good wiring and an ecu that people local to you can assist with.


And the temperatures are a fair point, neither are realistic. Although IR guns are crude at best

AW111

9,674 posts

140 months

Sunday 13th March 2022
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Paul Mann2 said:
happy fish said:
When I start the car up and let it idle for approx 5 mins I have a thermal thermometer, right bank approx 22 c left bank about 80 c .
Do you mean you are checking the exhaust manifolds with an infra-red thermometer? If so then both 22C and 80C seem unfeasibly low if you have cylinders that are actualy firing.
Seems more like head temps.

Scrump

22,944 posts

165 months

Sunday 13th March 2022
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happy fish said:
At the moment I don’t want to name the firm who I gave the car to but once I have resolved the situation and get the car running right I may name and shame.
.
nono
Posting Rule 5: Do not name and shame any company or individual, or post content which could cause reputational damage or which could be deemed as libellous or defamatory. To do so puts you at risk of legal action and we may be obliged by law to disclose your personal data.


I hope you get the car sorted.