Magna conversion surging on part throttle

[leoca]

Has anyone had a problem with their conversions where , the engine seems to miss when you are cruising at a constant speed.
I've basically put a magna engine in with TS injection (see "my build").Its got low compression.
The drivetrain seems to be unhappy with it and it can best be descibe. as a miss (sort of).The whole car seems to jerk.

Could it be the airflow sensor dirty.?I just adjusted the new TPS ...not much different.
Maybe has to do with the 2 plastic air thingys I had to cut out...you know between the sensor and the throttle body?.
Its fairly undrivable so if anyone has experienced this hccup and solved it .
Let us know...Cheers

[GB_BB4C]

I had this problem, but i had a lumpy cam installed. Removed the cam and it worked fine.
Are you running a stock cam??

[leoca]

Its the stock cam...for a 2.6 turbo Starion, but now converted to be run by a TR Magna loom and ECU (i.e. no turbo)...The engine characteristics would be different I guess.
Power peak at 5000.
I'm going to get new leads, plugs, CRC clean the air flow sensor, and run some injector cleaner next .Thnx

[leoca]

its a low compression engine (approx. 7.0 to 1), but its got TS Magna ECU,...what plugs would be best...i was happy to use TS magna ones...Champion N9YC???.

Does it make any diff?.

UPDATE : I have tried everything with no improvement
It has a vehicle speed sensor (the TR Magnas), maybe this condition needs to be "made happy"...does anyone else have this problem with their conversions?.
Does anyone know about speed sensors for the magna?

Maybe my fuel pump is too big/powerful?(VL turbo with stardard TP regulator)

[oldn64]

Just for a test, grab some small vice grips and pinch the return line for the fuel. This will escentially stop the regulator regulating. The car will run rich dont stress too much about it. go for a quick drive... is it still having the same issue? I suspect maybe a stuffed regulator, this will ensure the line pressure is right. However, if it only is rough on part accel and fine everywhere else then it will sound more like a tuning issue???? does it happen in all gears? do you have access to an exhuast sniffer or a air fuel log? what does the data log give? (not sure this is possible with magna system)

Cheers

[leoca]

...yes it happens in all gears,Thanks , i will try this out tomorrow.
It does run a bit rich...I do get a bit of a backfire between gears only ...maybe its some basic thing I missed...
I have put this down to my 3" exhaust system.
Am pretty sure the dissy is in the best position , although my timing light is cheap and nasty and have not relied on it...can't afford a good one.

they gave me spark plugs that were an NGK number 4 grading when i explained it was formerly turbo and lo comp.

[oldn64]

hmmm NGK 4 would be a colder plug IE less fins and so will over heat. I would have thought a 6 range would be better....? Are you fouling plugs badly...

If it is running rich then it might not be a reg issue. but still worth a try. The fuel maps are standard arent they?

Cheers

[leoca]

I am not fouling plugs at all, these new ones or the old ones .
Yes its just the TR/S ECU...all stock...was checked out by a diagnostic shop before the conversion.

[leoca]

UPDATE .Just spent a few hours on it this morning.

I went throughthe magna manual and there is a specific way that you must adjust and test the TPS .Adjusted the throttle stop again, and the TPS properly...what a pain I swapped the side on the conversion but anyhow got the right electrical results .

After a long drive the car ran better , better throttle response, and although still a little issue in 4th gear mainly , at around the 2-2500 rpm mark but nowhere near as bad.

[lchilds82]

hey im no expert but i was just wondering if you changed the fuel pressure regulator after gettting rid of the turbo, im pretty sure that turbo fuel pressure regulator work differently to the norm i may be wrong though, it may be getting real rich

[leoca]

I still have the stock one off a TP on it, goodness knows how old it is
Once I gat the car back I will look into it thanks...still there but much better.

[slo]

did you manage to sort this out by any chance?
im having a similar issue cept its around 1500-2000 very light throttle not so much missing more cutting completely in and out
i have replaced every thing, ecu afs coil igniter tps cap leads
any ideas?!?

[leoca]

The short answer is YES.
i seem to have solved the problem but not really!.
At present i have both the air flow sensor and the O2 sensors unplugged, and that along with a correction to my ignition timing has allowed it to run better than ever and its really beautiful now.
The surging on part throttle is no more.
The problem got worse in fact until about 2 weeks ago...back firing etc at low revs.The problem was with it leaning out.We did a few things and the mechanic is fairly certain that this starion engine runs a more aggressive cam...than the stock magna item.This meant that the TR/TS Ecu was getting confused.He says I can change the cam to a magna one and it'll probably be able to plug all the sensors back in .Cheers