Reading 0 Rpm Around 5600 Rpm

Disco702

Registered
So I have a Gen 1 motor in a mini sandrail. I ran a NA motor for the last 12 years. Over a year ago my bottom end went out so I picked up a new (used gen 1) with a turbo kit. Not sure the kit brand. pretty sure it's custom setup. Anyways. I'm running stock ECU with PC5. I got it in the car and started it up, got it on the dyno for tuning got started and we heard a terrible squeal. I tore the valve cover off and found one the cam had destroyed one of the journals and the head was ruined. I tore into the motor to find no oil gear had been installed. So I called the guy I got it from. He tore it down to check that nothing else was hurt and we pulled the head form my old motor to get it back running again. But now it has a new issue. When I throttle up it's like there's a governor around 5600 rpm just before the boost comes on. We plugged the computer in to the PC5 and found that around 5600 rpm it reads 0 rpm. So of course it cuts fuel then drops to where it reads rpm again and then kicks fuel in and revs back up to 0 rpm and you get the picture. We leaned it out real good right before that to get it to jump past that rpm point and it reads again and the turbo spools and she's a rocket. So the issue is just at that point. Any ideas? I can't find anyone else ever having this issue. I know a guy at dynojet so I'm going to have the PC5 tested but just wondering if there's anything else I should look at? I guess it could be in the ECU maybe?

20160326_160404.jpg
 

sixpack577

Top Gun
Donating Member
Registered
What year gen1?
99-00 are same ecu, 01 is different
And 02-07 are the same
02-07 are only gen1 years that ecu can be flashed.
99-01 can be upgraded to 02-07
 

Disco702

Registered
Than for the reply sixpack. This is now most likely the problem. I have a mish mash of years. So I just got off the phone with Suzuki to determine the years of my motors. My original engine was a 2004. So the ECU and wiring harness are from the 2004. The new engine with the RPM issue is indeed a 2001. That now has my 2004 head on it I might add. So what now? Obviously I'm going to need a 2001 ECU. But will my wiring harness be ok? are there any other engine management parts that don't click between those years?
 

Disco702

Registered
Altho if you can flash an 01 ecu on an 01 engine to be like an 04 ecu and it work on the 01 engine. Then I should be OK running an 04 ECU on a 01 engine? Is that right or did I just fall down the rabbit hole?
 

sixpack577

Top Gun
Donating Member
Registered
Altho if you can flash an 01 ecu on an 01 engine to be like an 04 ecu and it work on the 01 engine. Then I should be OK running an 04 ECU on a 01 engine? Is that right or did I just fall down the rabbit hole?

I just saw your post, sorry I missed it.
You don't need an 01 ecu.
You need a rotor and a couple other pieces from an 02-07.
Do you still have the bad bottom end from your 04?
Either way, sounds like an easy fix.
 

Disco702

Registered
I just saw your post, sorry I missed it.
You don't need an 01 ecu.
You need a rotor and a couple other pieces from an 02-07.
Do you still have the bad bottom end from your 04?
Either way, sounds like an easy fix.

I did some more research and rad about the rotor so I checked the rotor and it was the right one. I decided to pull the stator and Crank sensor from my 04 and swap it. I started it and it seams to rev past the 6000 rpm mark fine. I didn't push it because I know the tuning was not complete. I have my tuner stopping by tomorrow to have a look and see if she feels right now. I have high hopes.

I do still have my 04 bottom end. I intend to have it looked at, hopefully it was just the bearings and that the Crank is fine. Then I will get it rebuilt as a backup. Or maybe even build it big so I can swap back and forth for different riding applications. We'll see.
 

Disco702

Registered
Right on
Sounds like you've fixed it.

Thought I had it. I'm past the 0 rpm issue but still going haywire around 6000 RPM. I picked up a gauge cluster so I could pull F1 codes. I'm getting a C24 and C27 code when I rev over 5000 RPM. I've been reading thread after thread on this. Seams few have had this issue before but none as of the last 4 or 5 years and no one has posted a fix. I've tried swapping my coils around and spark plugs but issue stays on 1 and 4. I've tested my newer Crank sensor and resistance and peak voltage are good. I've checked peak voltage across all coils and the're all really close to each other. I've disconnected my PC5. Nothing changes. C24 adn C27 are plaguing me.
 

Disco702

Registered
I haven't looked at them. I assumed I'd get a code for those if there was an issue. No? I saw that someone on another post with similar c24 c27 issue said something about his primary injectors were good but he was running secondaries and they weren't firing. I don't have secondaries of course. Also saw something about the TPS maybe being out of calibration. What you think?
 

David Offor

Registered
Just been reading through this thread.
Have you had any luck solving your problem?
I'm having poor running below 3000rpm and misfire codes after 9000rpm on a 2000 gen 1, it's baffling at the moment.
I'm in the process of now changing injectors.
 
Top