Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[TheBoy]

Little Bro's car. We've been chasing a fault with this since he got it. Basically, it usually idles rough as hell, and at higher RPM, feels like its holding back.

LTFTs are at -12.% at idle (as low as they will go on this car), occasionally flagging a "Too rich" code.

When cruising, LTFTs raise to about -4%

Lamdas replaced, as old ones were looking a tad lazy. MAF replaced with a 2nd hand part, exactly the same readings as the original (within spec, but at the lower end of said acceptable values). Throttle Position Sensor reads slightly lower than what the internet implies at idle. New plugs as a matter of course (and other service items)


Oddly enough, he has never been able to change the fuel filter - he has tried several times with various filters from ECP and dealer, it never starts, until he puts original back in.

I've told him to go measure battery and charging voltages, but otherwise running out of ideas...

[chrisgixer]

Er, have I missed what car?

[TheBoy]

Er, have I missed what car?

Hyundai, but not sure that makes a difference

[chrisgixer]

Er, have I missed what car?

Hyundai, but not sure that makes a difference

Ok, have it your way.

[TheBoy]

Er, have I missed what car?

Hyundai, but not sure that makes a difference

Ok, have it your way.

Me no understumble 

[martin42]

No comment..........
Strange as no other filter will work apart the original 1 fitted .

[TheBoy]

No comment..........
Strange as no other filter will work apart the original 1 fitted .

Yeah, we're wondering if some bodge was put on it to make it run well enough to sell.

Other thoughts, FPR faulty, not sure how to check without buying a tester, and finding a way to test it (there is a unique Hyundai adapter on this car.

[Andy H]

No comment..........
Strange as no other filter will work apart the original 1 fitted .

Yeah, we're wondering if some bodge was put on it to make it run well enough to sell.

Other thoughts, FPR faulty, not sure how to check without buying a tester, and finding a way to test it (there is a unique Hyundai adapter on this car.

So.

blocked fuel filter + faulty (or bodged) FPR = slightly high fuel pressure at idle & low pressure at full throttle.

[martin42]

What about refitting new fuel filter but dont connect the outlet side,then see if there is fuel coming out when pump primes.

[TheBoy]

No comment..........
Strange as no other filter will work apart the original 1 fitted .

Yeah, we're wondering if some bodge was put on it to make it run well enough to sell.

Other thoughts, FPR faulty, not sure how to check without buying a tester, and finding a way to test it (there is a unique Hyundai adapter on this car.

So.

blocked fuel filter + faulty (or bodged) FPR = slightly high fuel pressure at idle & low pressure at full throttle.

Its very rich at idle, and quite rich at higher revs. Hence FPR being considered.

Blocked filter? The 3 replacements have all prevented the car starting...  ...though obviously I'm suspicious of something around the filter if only the original one works...

[TheBoy]

What about refitting new fuel filter but dont connect the outlet side,then see if there is fuel coming out when pump primes.

I'm sure when he tried the first replacement filter, he confirmed he had a good fuel flow to the injector rail.

[Andy H]

No comment..........
Strange as no other filter will work apart the original 1 fitted .

Yeah, we're wondering if some bodge was put on it to make it run well enough to sell.

Other thoughts, FPR faulty, not sure how to check without buying a tester, and finding a way to test it (there is a unique Hyundai adapter on this car.

So.

blocked fuel filter + faulty (or bodged) FPR = slightly high fuel pressure at idle & low pressure at full throttle.

Its very rich at idle, and quite rich at higher revs. Hence FPR being considered.

Blocked filter? The 3 replacements have all prevented the car starting...  ...though obviously I'm suspicious of something around the filter if only the original one works...

Sorry, didn't explain myself.
Try "partially blocked filter" + bodged FPR that doesn't limit the fuel pressure.

At idle enough fuel gets through for a rich idle.

At full throttle there isn't enough fuel (due to partially blocked filter)

Is the return to the tank OK? (has it been crushed or has someone put a restriction in the pipe perhaps?)

A new filter (with very little resistance) resulting in far too much pressure at the fuel rail.

[TheBoy]

Understood, I'll get him to check . He was going to check the return anyway for restrictions.

[Martin_1962]

Hyundai, sell for scrap!

[cem_devecioglu]

Er, have I missed what car?

Hyundai, but not sure that makes a difference

if it has 4 wheels , sucks air and fuel and pumps out burned exhaust gas.. it doesnt really!