I'm still in the process of trying to get my car drivable so I can begin breaking my motor in, but everytime I start the car it runs really rough. I understand they usually do first couple hundred miles. But if I hold the throttle at 2k. It will jump randomly and rev smooth to ~2500 then drop back to 2k and run rough again. Backfiring occasionally.

Also after about 5 min the cat started glowing bright red and eventually the hotside of the turbo did too so I shut it off.

I unbolted my exhaust, removed the cat and it looks perfectly fine. What's going on?

 

The most likely scenario is the timing is off. Restab the CAS and check with a timing light. You'll have to have the RPMs below ~1100 to check it. The ECU will advance timing above that point.

An exhaust restriction is also a possibility.

 

Alright will do. I already tried doing that but I'm gonna do a once over the motor then retry the cas again. Maybei got it wrong. Ill let you know how it goes

 

Alright so I redid the timing and started up again.
It idles smoothly at 1k :]. No red turbo.

Now only issue is studdering under throttle..bad fuel? Or tps or low fuel pressure?

 

thats what sucks about new motors. I have a new mazda reman. new rotors and housings. and i just put 40 miles on it and it still intermittantly floods when i restart it when it is still hot.

make sure you have your tps adjusted and timing set. you have to jump the connector by the coils and check it with a timing gun..

check your alternator output too. should be 12-14 volts. mine was on its way out from sitting for 9 years and causing my fuel pump to be weak

 

I just got done tinkering around with it. I havent checked the TPS yet or anything for that matter.
Before i pulled the motor it ran perfect..minus the billowing smoke lol.

but im going to check the TPS tomorrow afternoon. As it stands right now the car idles. when it studders, itts like it gets stuck at the RPM its at then breaks free and finally revs. Im going to try and get a video of it. Its still backfiring..loud. Timing is set. no Vacuum leaks. as far as i can tell.

Idk about my fuel idea anymore. I was thinking m,aybe dirty sock on the fuel pump or fuel filter nut it wouldnt explain the backfiring. Or does the fact i blocked off my EGR have any effect on this?

 

I have my egr and acv blocked off. I have no problems like that. Check tps

 

Alright so.

I've double checked once again over the motor and no leaks ect.

I set timing again. It wasn't off at all.
I also checked my TPS and the resistance was off quite a bit. At first it read 2.72 ohms at closed throttle. And 7.83 at WOT. Ran the motor bacl to op temp and reset it to 1.08 ohms but it still reads 7.26 at WOT. Started the car and nothing has changed. Still studders. I've checked spark and its there.

I even unhooked the TPS to see if it ran different. Didn't idle. But still had a studder under throttle.
And alternator tested 14.1 volts..like a boss haha

 

You could also disconnect the hose to the Boost/Pressure sensor and plug it and take it for a ride to see if there is any improvement.

 

Matt get off my car your going to dent my hood. :P

 

If it runs better with the sensor plug what's that indicate??

 

So the car ran worse w/the vacuum hose removed and plugged from the sensor?

Also, check the TPS using the voltage method. W/car as warmed as can be the G/R wire of the TPS pigtail ought to read 1 volt w/key to on. The ohming method might be inaccurate if the wire is old and causing extra restance to occur. Also, when the throttle separates from the TPS plunger the voltage reading should read close to 5 volts.

 

Yea the boost sensor idea changed nothing..
And the tps read above 5 at wot fully warmed up. Reads 7.26. I'm gonna go try to borrow a friends to see if it changes. Other than this I'm all out of ideas

 

Your 7.26 reading is ohms and I'm suggesting you use the "voltage" method which is not the same as ohms.

 

Ohh sorry. I'm not very good with electronics and such. Lol. What is the voltage method?

Also I just tried someone esles tps and it sounded abit smoother. But the studder was still there. It was a noticable improvemnt though.

 

One more time. You warm the car up as warm as it can get then w/key to on measure the voltage of the G/R wire at the TPS pigtail and it should read 1 volt. If it doesn't then adjust the TPS screw til it measures 1 volt. When the TPS plunger is fully extended it should measure 5 volts, so at idle it measures 1 volt and w/the plunger fully stuck out it measures 5 volts. If you want to measure for voltage you set the meter to DC volts!