Suzuki Sidekick swap drivability problems...

So several years ago I swapped an AHU engine into a Suzuki Sidekick. It's been a great little run around car for many years. Initially it was suited using a mechanical pump, but recently I ended up moving to a ALH pump. Thought it might be better. Turns out it's really not much different than the mechanical pump, but now I've got issues. Low RPM/low speed chugging around (like off road) sometimes there is a series of lurches that occur. It's difficult to describe, but the engine speed seems to 'bounce' between acceleration and deceleration very rapidly. The only solution is to depress the clutch and start over.

I'm using Malone tuning, and have asked him to decrease throttle sensitivity, but I was wondering if there was a way to do this with VagCom. Would an IQ adjustment help at all? Currently IQ shows 4.8. It's difficult to do this with a tuner, what with the distance and all.

Any ideas?

I don't have an idea of what the problem is, sorry. But I do think it's probably not throttle sensitivity. Malone has done zillion tunes and yours shouldn't need something special.

Somewhere in Vagcom must be a way for you to see throttle % which is what the computer is seeing. That might help.

are you running a 10 or 11mm ?

It's a 10mm pump. I initially had QA codes from this pump, but have been using it for a year or so without codes.

I've driven other diesel vehicles (with manual transmissions) that exhibit a weak version of this behavior when cold, but nothing like this...

Did it:

1) start to misbehave immediately after you did the tune
2) behave fine with the tune and then one day suddenly start to misbehave
or
3) behave fine with the tune and is now gradually degrading

i can get my truck to start an oscillation but it's 100% the engine mounts, only happens at low speed and i correct by stabbing the clutch and starting over... not saying this is your issue just an anecdotal data point to add confusion ...

swap tunes are generally pretty butchered with a zillion trouble codes disabled
that said, it could easily be the pedal rheostats or wiring
driveline oscillation like described earlier ITT can also usually be dampened by just mashing the pedal to its stop, as in my case at least it is from the car's bucking moving me in the seat and on the pedal.

diagnostics over the phone can be tough as heck

So here's the other thing...

I have another one of these vehicles that is running the exact same setup BUT the other car drives very nicely. ALH pump on an AHU engine with Malone tuning. I've swapped the ECU's, it does not change anything. So I'm thinking that it is either the pump or the throttle. It's odd, even without lurching the 'good' car has a pretty different feeling to the throttle.

The plot thickens...

Just tried swapping the accelerator pedals between the two cars, no difference.

Could there be a fault with the IP causing this? No pump codes, however.

Vince Waldon said:

Did it:
1) start to misbehave immediately after you did the tune
2) behave fine with the tune and then one day suddenly start to misbehave
or
3) behave fine with the tune and is now gradually degrading

Click to expand...

So I went from a mechanical pump to an Electronic setup all at once (including the tune). Ran great with the mechanical pump.

It was really bad initially and I had Malone smooth things out more, which helped some but I think my tolerance to the improved version is deteriorating.

swap pumps, i had one that exhibited surging and different pump cured it... again, not saying it's the cause, but super easy swap out

I'll be on the lookout for a fresh pump then!

I looked for it, but it seems as though no one sells the QA mechanism to swap out of the pump?

mannytranny said:

I'll be on the lookout for a fresh pump then!

I looked for it, but it seems as though no one sells the QA mechanism to swap out of the pump?

Click to expand...

bosch might? Be hideous expensive though
I'd find a junkyard or used pump to swap top ends from

QuickTD said:

Do you have a clutch switch wired up? The IQ "rate of change" differs depending on whether or not the clutch pedal is depressed. Much quicker throttle response when pressed.

Click to expand...

great idea, that could cause this type of behavior.

No clutch switch on either car...

So without a switch the ECU would read as clutch depressed and the quicker throttle response would cause the surge?

Ya, no fault codes for either car...

So I sent the pump to DFIS. Reinstalled yesterday and the car runs so much better. Engine feels smoother, quieter and the surge issue is gone.

Thanks for the advice gents!

Did you ask what they did to the pump, or what was faulty? Glad you got it sorted out.

-Todd

Ya, low speed QA voltage out of spec. Didn't throw a code, however.

Something else was wrong too, but I can't recall specifically. I don't buy used pumps anymore. Been screwed in the classifieds here three times now!