Venture MP not running great

[Mooseman]

changed mine today but still misfires after warming up dealer tells me recall on wiring harness could be the issue so going in this week they do recall free so i ll you know what they come up with

Just one or both? If just one, maybe it's the other?

 

[venture lite]

bck from dealer ya groud and block replacement .but found problem very small oil leak at head cover gasket at plug causing misfire seems to be fixed something to look for gasket 20.00 dollars coil 120.00 hope it helps.

 

[Mooseman]

I have never seen an oil leak on a valve cover cause a misfire. Oil fouled plug maybe but not valve cover.

 

[Ice_fisher]

I have seen the spark plug tube seals leak soaking the spark plug and over head coil and deteriorate the insulator on the coil and cause the coil to arc out through the boot. I just got my new coil and boom wrong one even once the dealer took my seri number

 

[Ice_fisher]

Serial number the parts was ordered on December 28 rush order time to find another dealer.

 

[YukonMP]

Man that sucks, I hope you get a break.

 

[Ice_fisher]

Well everyone I am stuck changed over coil one, went for ride no difference. Put old coil one on cylinder two went for ride no defferance. On ride noticed it would only get up to 125 km/h and then only 106 km/h. Shut off and rode again got only 125 km/h and runs rough at any speed and will stall out if I hammer on the throttle. I just drained the fuel and ran some injector cleaner through. I will put fresh premium fuel in tomorrow and re test. No engine codes no blinking D no codes. Any other suggestions?

 

[YukonMP]

What about a partial clog/restriction somewhere in the fuel system?

I re-read this thread for background. Did this thing run right at all since coming out of storage? Was it stored with ethanol gas?

 

[Mooseman]

Has anybody mentioned the throttle position sensor? Maybe it needs to be checked and adjusted.

 

[YukonMP]

No, that has not been mentioned and my 2014 service manual lists it as a possible cause that won't throw a code.

The complete list is TPS, intake air pressure, speed pulse, fuel system voltage, coils, injectors. Don't know if that helps but maybe something will jog someone's thinker.

 

[Ice_fisher]

Hi All, I went through the diagnostic mode before I ordered the coil checked tps ok, check map sensors ok, checked injector pulse ok. Check speed pulse ok, checked battery voltage ok. Checked air intake temp and coolant temp sensor ok. Replaced plugs still misfire. Replaced coil 1 misfire tried coil 2 misfire. I also checked TORS. I disconnected sensors well engine running to make sure engine light and ECU are communicating and they are. At the start off the season I drained most off the fuel put fresh in maybe 1/4 tank of old 1/4 tank of fresh. So know I have drains all the fuel it smells a bit funny but cold be the sea foam Heavy dose. I will fill up with fresh premium today and re test.

 

[Ice_fisher]

Well re tested still a miss fire and found it was backfiring through #2 intake. Took out injectors cleaned them re test still no good. Starts off ok then miss fire and rough run. If it is back firing through the intake when hammering on the throttle and not 100 percent when hitting the throttle hard and can't reach max rpms at times I am leaning towards low fuel pressure, pump, regulator, or maybe ECU.

 

[Mooseman]

I would rule out the ECU. It either works or it doesn't. Wouldn't be a bad idea to do a compression test to rule that out right away.

Could be a bad injector too. Maybe once warmed up, it craps out.

 

[Ice_fisher]

Hi Mooseman,
This is a weird problem tested injectors and both spraying good. I am leaning towards fuel pressure being low do to the fact it is backfiring through the intake # 2 and not as much power as when it was not doing this. And the fact it is ok for a bit and worsens the long you drive and the harder you push it. Around mid throttle it is bad and sometimes you can throttle it up it gets a bit better but still a miss there. It is acting like a bad coil. Don't want to keep throwing parts into
It. Man disappointing hit 2000 miles and hasn't ran good since.

 

[Mooseman]

It does sound like a fuel supply problem. So you hear/see it backfiring in #2 intake while in the shop on a stand? Does it stay in #2 when you swap the ignition coils?What about the fuel injectors? Did you swap those?

Yeah, it can get expensive throwing parts at it, especially something like a fuel pump or regulator. You do have a copy of the repair manual? It has a whole section on the fuel injection system.