Engine surge when warm

[smokeyo1]

Hi all
I have just transplanted a 1UZFE and am getting an engine surge once warm, the code diagnostic gives me a code 28 which is main oxy sensor right bank, Ive swapped the over and still get the same code and the same surge, the unit was built with four sensors, but previously two were junked along with the cats, any one had this, and whats the cure?

 

[Bushwhacker]

Did you clear the codes after swapping 02 sensors?

 

[samsdad]

I've had this problem on 3 vehicles, Two were conversions (1UZ into Hilux/Surf) and the other a '91 LS400. I had 3 different engine management systems which were '95 Celsior (4 wire main and sub O2s) '91 Soarer (1 wire main O2s and no subs) and obviously the LS was stock (4 wire mains and 2 wire subs). All when warm appeared to "surge" when warmed up and under load or sometimes cruise and all fired the R/H main O2 code 28.

It did take a bit of finding as to what the cause was but it turned out to be a faulty ignition coil which effectively shut down 4 cylinders under load. A set of new coils later and problem solved

 

[extractors]

Yeah the left bank coil is prone to that,

I'm losing a heap of torque/power when hot ? I'm assuming water temp is too high, flies when cold and then just dies around town when its warmed up.

 

[samsdad]

Yeah the left bank coil is prone to that,

I'm losing a heap of torque/power when hot ? I'm assuming water temp is too high, flies when cold and then just dies around town when its warmed up.

I'd check the temp at operating temperature using a master or IR gauge to ensure that is within spec. Then replace the ECT sensor to start with. Keep in mind that dirty injectors can be an issue esp with this rubbish that they try to pass off as petrol now days along with stale fuel if you've just done a conversion.

I've just changed to larger green top injectors which in itself proved to be a drama as I purchased every injector that poorsupra could get his hands on, wasn't the purchase that was the issue it was getting auspost to deliver the damn things.. But after coils, ECT sensor and given that I'm now an automotive teacher rather than a mechanic so have nice toys to play with at school (injector service and test bench), I have a "Get in, shut up and hang the hell on" 1UZ powered Surf rather than just "Hang on".

Now given that I've just gone to teaching automotive theory and yes this is relevant to this thread. I will say that I've forgotten probably more of that than I know and now have to remember all of it, and read the books again. But basic diagnosis is when you get a code that is the result of a symptom and not a cause. OBDII and later systems will give you more of an indepth way of trouble shooting but remember this. BACK TO BASICS!

You need to study basic automotive theory as to how everything works so you can sort the problem. With a conversion if you've wired it up right it will start and run and drive but there's plenty of other variables that can cause issues and DTCs (Diagnostic Trouble Codes). We can say what a problem is from our own experience which may sort your problem and hell I often refer to the forums when under the pump just to jog my own memory

 

[extractors]

I'm sure the water temp might be the issue, the radiator is from a 76 model mercedes

My v8 soarer flies hot or cold, so going to some testing on that and see what the temp does first, then I have a baseline, I believe operating temp should be under a 100 C. Ive read timing starts getting pulled at around 110 C, however I think the look up maps possibly remove some even earlier than that.

Does anyone know if you can get fittings that will tap a mechanical temp gauge into the factory dash temp sensor port ?

Smokey, sounds like you might have to add the other two sensors and cats back in the system, I don't believe they can just be deleted without other work.

 

[gloverman]

The cats and rear sensors can be removed without an issue. If you keep getting an oxy code on the same side it points towards a fueling issue related to that side such as an air leak mainly on one cylinder or injector issue or a misfire on that side or could also be an exhaust leak at on that side infront of the sensor.

 

[extractors]

Ok, thought it was the later model 4 o2 sensor, but yes heat sensors can be ditched.

 

[smokeyo1]

Thanks for the input guys, sorry I should of given you a bit more info on the engine, its a 1990 v8 4litr, I used the engine loom from the donor.
Samsdad: thanks for the tutorial, that exactly what I did, I went back to basic engine management.
Turned out for some reason that the oxy sensors were not getting their fair share of the 12volts, only .6 on the left and less on the right? so I ran another power from B+ on the ECU and alls good, sweet as a nut, I trusted the engine loom as the vehicle ran fine before, or so I was told, huh, maybe not

 

[samsdad]

smokey remember where the wiring runs for the O2s. Under the exhaust manifolds. While it is shielded it can degrade and fall apart over time. Sounds like you've found the problem but