Problem with the new tudor

[Cadillacmob]

I bought the infamous tudor 85 from Zach, since owning it I've installed a explorer 5.0, Gt40 heads With Alex springs , HO cam, 1.72 rockers , 19 pound injectors , 89 mark VII speed density computer and gt40 intake with explorer throttle body.

Now the problem !

Sometimes Ill be driving along and it feels like a bad miss where it boggs down. And pops through the intake. It's intermittant though. Other times the car scoots like a rocket. It will intermittently stall also. Sometimes it will idle fine but what I noticed is when it won't idle right that's when it runs bad. I've verified fuel pressure and installed a adjustable regulator and set it at 40, new msd cap and rotor , ford racing wires, plugs , new msd coil.
Zach installed a upgraded fuel pump.

It's weird though. Sometimes the cars a rocket. Others ot just feels like I have 2 wires crossed. Anyone have ideas for me ?

[Chuck Norris]

My car had the exact same symptoms with a bad fuel pump, and even if the one in your car was brand new and installed yesterday, it could have prematurely died. However, having good fuel pressure makes this extremely unlikely. The symptoms also sound like a bad Mass Air Flow sensor. Try driving it with the MAF unplugged and if the symptoms go away, it is (likely) your culprit. Unless you have a scan tool and can start looking at the data. If you don't, I know that O'Reilly stores usually have an OBDI compatible code reader, and they have one of the old ford hookups. I don't even know what system you would use in your car though, as it is so far from stock.

[Cadillacmob]

Thanks for replying , I want to moniter fuel pressure while drivin somehow. I initially thought fuel pump also. The problem did get a little better after the new regulator went in but still is not good. I forgot to add I did a fuel filter also. My cats still speed density though

My car had the exact same symptoms with a bad fuel pump, and even if the one in your car was brand new and installed yesterday, it could have prematurely died. However, having good fuel pressure makes this extremely unlikely. The symptoms also sound like a bad Mass Air Flow sensor. Try driving it with the MAF unplugged and if the symptoms go away, it is (likely) your culprit. Unless you have a scan tool and can start looking at the data. If you don't, I know that O'Reilly stores usually have an OBDI compatible code reader, and they have one of the old ford hookups. I don't even know what system you would use in your car though, as it is so far from stock.

[Grand Marquis GT]

It seems that some of these slightly hotter than stock builds make the speed density ECMs play funny. My old 87 with around the same amount of work done did the same kinda stuff. John (86VickyLX) had some similar issues and it turned out to be cris-crossed O2 sensor plugs. Dumb, I know.

[Cadillacmob]

You know what my buddy has been telling me this and I've totally neglected switching them. In fact when I bought the car from Zach he had the harness unplugged and in the trunk. I just guessed which aide to plug in. I'm gonna switch them tomorrow and try !

It seems that some of these slightly hotter than stock builds make the speed density ECMs play funny. My old 87 with around the same amount of work done did the same kinda stuff. John (86VickyLX) had some similar issues and it turned out to be cris-crossed O2 sensor plugs. Dumb, I know.

[gadget73]

yeah the oxy sensor reversal thing will give you a lot of shit. Its not obvious which side goes where either, the wires are the same length and usually burned to all being the same colors even if you did happen to have the manual to tell you which color goes where.

[Cadillacmob]

You guys were right. Thank you guys a lot. I switched the plugs and the car drives awesome. I appricate it

[86VickyLX]

You guys were right. Thank you guys a lot. I switched the plugs and the car drives awesome. I appricate it

I'm happy to hear your issue was solved! And that you didn't drive the car for 2 years dealing with it like I did haha!

[87gtVIC]

I hear this happening a couple of times now and am just curious as to how this is happening.



Above you can see the 02 harness. The small ground cable attaches to the drivers side rear lower intake stud.

The large ground cable attaches to the passengers side head at the rear.

The large ground is harnessed in with the passengers side 02 sensor and if everything was restored to stock I don;t see how these can be crossed up.

Do others have 02 harness look like mine or are they different?

[86VickyLX]

You can physically flip the harness backwards. They will reach either way.
88+ ditched the extra ground. So you could mess it up.

[87gtVIC]

That would mean the grounds were not restored to the stock location then wouldn't it?

[86VickyLX]

sure. I've also seen the orange ground stock on the passenger side of the harness. My 86 originally had it on the passenger side.

[Chuck Norris]

I'm glad it wasn't anything major.

[Cadillacmob]

It's easy to do, since I bought the car as a roller I really didn't habr much to follow. Also I believe I messed up because the factory manifolds have 02 bungs. I have stainless headers with no O2 sensor bung. I instead used a fox mustang off road h pipe so the wiring is pulled down Id estimate about 6 inches or more. So the stock grounds won't reach. I had to ground on the bell housing

[Cadillacmob]

Now a new problem has arised. I failed the KOER test. Code 10 problem with cyl 1. I am wondering if I have a lazy injector. Also have a lean code