Suxuki GSXR 1000 DSR/P2 engine help

[Riverside Racer]

Hi All,

I'm chasing a gremlin in my 2004 GSXR 1000 engine. This is my first stab at a FI cycle engine car.

I acquired this car back in November and haven't had the engine up to speed yet. Supposedly it's a stock GSXR 1000, so I'm not expecting any "trick" setups.

The engine idles great at 2,000 rpm. I'm not getting to rev above 5,000 rpm. It's not crisp and with the occasional pop / backfire.

I've replaced:
Crank Position Sensor
Cam Sensor
Coils
Plugs
Rebuilt the injectors
New fuel pump and 100 micron filter
New wiring harness
Swapped ECU's
Primary throttle position sensor
MAP sensor
Air temp sensor

I feel like I own a British car again
(I formerly raced an HP Bugeye)

George Dean was kind enough to suggest fuel flow, thus I did the the work on the fuel side.

I have a secondary throttle position sensor coming in today. It's the last bit of electronics to be swapped.

I'm about to check the cam timing.

Open to any suggestions or help in the Orange County, CA neighborhood.

Thanks,
Steve

[Racerex1]

Hi All,

I'm chasing a gremlin in my 2004 GSXR 1000 engine. This is my first stab at a FI cycle engine car.

I acquired this car back in November and haven't had the engine up to speed yet. Supposedly it's a stock GSXR 1000, so I'm not expecting any "trick" setups.

The engine idles great at 2,000 rpm. I'm not getting to rev above 5,000 rpm. It's not crisp and with the occasional pop / backfire.

I've replaced:
Crank Position Sensor
Cam Sensor
Coils
Plugs
Rebuilt the injectors
New fuel pump and 100 micron filter
New wiring harness
Swapped ECU's
Primary throttle position sensor
MAP sensor
Air temp sensor

I feel like I own a British car again
(I formerly raced an HP Bugeye)

George Dean was kind enough to suggest fuel flow, thus I did the the work on the fuel side.

I have a secondary throttle position sensor coming in today. It's the last bit of electronics to be swapped.

I'm about to check the cam timing.

Open to any suggestions or help in the Orange County, CA neighborhood.

Thanks,
Steve

I didn't see where you had checked fuel pressure on the line. Stock FI Suzuki's require a pump that gives at least 40 lbs. of pressure. I have run higher with a built motor.. Carbed engines 3-5 lbs. of fuel pressure.

Dick

[Onebadbug]

I would suggest you send the ECU to George Dean, and have it gone over for all the "safety" features. Tipover switch, etc. The only thing he couldn't fix for me was the secondary throttle failure message.

[Riverside Racer]

I didn't see where you had checked fuel pressure on the line. Stock FI Suzuki's require a pump that gives at least 40 lbs. of pressure. I have run higher with a built motor.. Carbed engines 3-5 lbs. of fuel pressure.

Dick

Thanks,

Yes, 50lbs fuel pressure, constant.

[Riverside Racer]

I would suggest you send the ECU to George Dean, and have it gone over for all the "safety" features. Tipover switch, etc. The only thing he couldn't fix for me was the secondary throttle failure message.

Thanks,

I had the wiring harness put on a diet to remove all the unneeded items. That tip over switch got me when I first got the car!

Secondary TPS change happening today or tomorrow.

[David Ferguson]

I would make sure you have the correct injectors for the engine/ECU. I worked on one particular engine (not a bike engine) where we changed injectors, and while they had the correct flow, the didn't have the same atomization, and wouldn't rev stopping at 4-5k RPM regardless of throttle.

A bad throttle position sensor can cause this as well if the ECU doesn't understand how much air is getting in the engine. Verify with a voltmeter that the voltage is changing. Perhaps in "thinning" the harness, you failed to connect a shared power or ground to the TPS, Baro or MAP sensor -- all of those are critical.

[Riverside Racer]

I would make sure you have the correct injectors for the engine/ECU. I worked on one particular engine (not a bike engine) where we changed injectors, and while they had the correct flow, the didn't have the same atomization, and wouldn't rev stopping at 4-5k RPM regardless of throttle.

A bad throttle position sensor can cause this as well if the ECU doesn't understand how much air is getting in the engine. Verify with a voltmeter that the voltage is changing. Perhaps in "thinning" the harness, you failed to connect a shared power or ground to the TPS, Baro or MAP sensor -- all of those are critical.

Thanks for the input David.

I'm resetting both TPS and STPS values.

"It's always the GROUND". I'll check and maybe add a couple to be sure.

[924RACR]

FYI, to my knowledge a bad cam sensor will allow the engine to run... but it won't start! So if it's starting, odds are you don't have a bad cam sensor!

I don't believe the secondary TPS would cause this issue... I don't run one, though I run an '08...

What else... make sure the MAP sensor vacuum lines are all connected, I almost seem to maybe recall having a similar problem when I once had that disconnected on one or two of the venturis...

Another thought; though you've been through all the coils, plugs, and injectors, is there any chance you're down a cylinder or two still? Quick easy sanity check for this, if you have an IR pyrometer, just look for a cold runner on the header after a run-up...

Good luck...

[10rmotor]

What pressure regulator do you have?

[Riverside Racer]

What pressure regulator do you have?

Aeromotive

with 100 micron Earls filter before the pump.
New Walbro fuel pump. Holds 50# all the time.

[VSeaber]

The secondary injectors are phased in somewhere around that RPM. Check wiring to the upper injectors, also switch upper and lower injectors to see if you can move the problem. If the car has sat for a long time the uppers may be gummed up and need to be cleaned. I had that happen on a car that sat for a couple of years.

[Riverside Racer]

The secondary injectors are phased in somewhere around that RPM. Check wiring to the upper injectors, also switch upper and lower injectors to see if you can move the problem. If the car has sat for a long time the uppers may be gummed up and need to be cleaned. I had that happen on a car that sat for a couple of years.

Thanks for the idea.

This K3/K4 series engine only has one set of injectors.

I had them rebuilt RC Injectors. The problem persisted.

[Riverside Racer]

After chasing this for too long, I've settled on a somewhat simple solution!

I've swapped it all out for a complete 2005 K5 series engine

I changed the front engine mounts on the car and a little revamp of my wiring. I hope to fire it up shortly.


I'll be selling the complete K3 /4 engine, extra throttle body and two ECU's.
I'm sure someone (else) can figure it out.

[10rmotor]

You may want to upgrade to a ten micron filter. 100 is too big.