98 srad fuel problem : Suzuki GSX-R Motorcycle Forums: Gixxer.com

**Srad7fiddy** · 07-26-2010, 09:28 AM

Has anybody heard of a fuel pump having right psi but putting out to much fuel I think that is my problem

**GSXR-Freak** · 07-26-2010, 09:44 AM

on a 98 750 the pump can not pump too much. That is the idea of the fuel pressure regulator.

What makes you think that you have this problem?

John

**Srad7fiddy** · 07-26-2010, 10:00 AM

I get 70 miles to a tank and I have done everything else

**TT750** · 07-26-2010, 11:30 AM

Have you checked your plugs and filter?? Maybe run some cleaner threw it. If the regulator wasn't working and not dumping the extra fuel in the engine. It would rub extra rich.

**GSXR-Freak** · 07-26-2010, 12:25 PM

70 is bad, but I doubt the pump the problem.

You say everything else, what all have you done?

John

**Srad7fiddy** · 07-26-2010, 03:03 PM

This is all the mods and what I have done
+1 in front, d&d slip on, k&n, 190 rear, tre, pc3 USB ( not hooked up) last oil change was bout 400 miles ago air filter was charged then aswell new ngk plugs I do not know if or when the valves were adj it is not throwing any codes I don't know if there is any power loss or not b/c it has done this scense I bought it
The things I have done to try to fix it r new plugs new oil and filter throttle bodies sync new fuel pressure regulator new injectors new fuel rail new throttle bodies new tps new air temp sensor and vacume boost sensor
I have had it on a dyno 4 times every time I've done somthing I would see if it made a difference in my fuel curve but it didn't I've had the yosh cube hooked up to it also

**GSXR-Freak** · 07-26-2010, 03:06 PM

what type of HP numbers from the dyno, also what was the a/f ratio at on the dyno?

John

**Srad7fiddy** · 07-26-2010, 04:49 PM

Hp was 110 and can't remember about the a/f but he said it was outrageous

**GSXR-Freak** · 07-26-2010, 05:20 PM

I feel like we have gone over the problems listed with your bike...

Have you tried to test the sensor on the back of the airbox, I think it is intake vacuum.
There is also a barometric sensor on the right hand frame rail, you should test that.

If those both check in spec, I would look for a loose ground and then a replaced ECU.

John

**Srad7fiddy** · 07-26-2010, 06:11 PM

How would I check those sensors out
And would a loose ground make it run like that ??

**GSXR-Freak** · 07-26-2010, 11:13 PM

If you had a loose ground it could cause all sorts of problems with the timing on the injectors. It COULD cause them to pulse twice I guess.

The sensors, you would need to refer to the factory service manual. I do not remember how to test them.

If you dont have it, you can search this site, many people have posted links to the manual and I think one member has it in his sig..

John

**TT750** · 07-27-2010, 09:58 AM

Chocolate rain has link to service manual in his sig

**Srad7fiddy** · 07-27-2010, 03:52 PM

Do I need to just check the ground from the bat to the frame
If there is more any hel would b appreciated

**pentiumpush** · 07-27-2010, 08:50 PM

Your fuel pump is definitely not putting out too much fuel. Also, if you have bad grounds for the sensors, they will send false signals to the ECU which would, in turn send the signals to the injectors and coils.
You said you replaced the TPS sensor. Did you do the correct procedure to reset the output voltage on it? (put bike in dealer mode, get engine to normal operating temp., make sure choke all the way off, set TPS for correct reading on gauge cluster)
Now, three things I didn't see that you checked/replaced are as follows: (1) Battery, (2) Both fuel filters, (3) Connections to rectifier/regulator. Also check for loose/bad vacuum lines and throttle body rubber boots.

**GSXR-Freak** · 07-27-2010, 09:52 PM

If the fuel filters are dirty, it would not supply too much fuel.

Battery maybe, but likely you would have other problems long before the FI would be a problem.

I would lean more on the side of a vacuum problem or a miss routed line causing a sensor to read incorrect.

John

**Srad7fiddy** · 07-28-2010, 09:16 AM

I did the procedure u said on tps I got online and found all the specs on all the sensors. So I will check those out
R both filters in the tank

**TT750** · 07-28-2010, 09:44 AM

filter is the pickup screen and a filter inline as part of the fuel pump assembly. Check out the parts Fuchs at Ron ayers

**GSXR-Freak** · 07-28-2010, 10:05 AM

I would leave the filters to the end. A clogged filter = less fuel, not more.

John

**Lean With It** · 07-28-2010, 11:41 AM

have you checked for leaks around the fuel pump gasket? You may have a small enough leak where nothing hits the ground as it evaporates on the block. Are you getting gas in your airbox?

I would think if the ecu is getting bad signals or the injectors are firing or pulsing twice in a stroke, you get some kind of bog or your spark plugs would be soaked.

I'm curious to the HP numbers and a/f numbers from a dyno run.

**EVIL_SRAD666** · 07-28-2010, 12:42 PM

I had the same issue on my 98 750. Check the water temp sensor. your bike is maybe getting a skewed signal from the water temp sensor and the fuel injectors signal from the ECU think the bike is always cold. in turn making your bike run pig rich.