New motor will not idle

[AbsoluteSpeed]

I just had the motor re-built less than a week ago.
When ever I push in the clutch between 2500-3000rpm (this is the highest I let it go at this point) and let the rpms drop the car stalls. This is annoying but I can drive around it.

Today, after work the car would not idle at all.
Every light I came to the car stalled. If I started it again it would start, go to 1100rpm (like normal) then immediately stall again. I let the car warm up before I drove, it was not at normal opperating temp but only slightly below when I started driving. Once I was about half way home the idle evened out and everything was fine.

Any ideas?

 

[87n/a_supra]

check the TPS and the AFM

 

[dumbo]

I just had the motor re-built less than a week ago.
When ever I push in the clutch between 2500-3000rpm (this is the highest I let it go at this point) and let the rpms drop the car stalls. This is annoying but I can drive around it.

Today, after work the car would not idle at all.
Every light I came to the car stalled. If I started it again it would start, go to 1100rpm (like normal) then immediately stall again. I let the car warm up before I drove, it was not at normal opperating temp but only slightly below when I started driving. Once I was about half way home the idle evened out and everything was fine.

Any ideas?

Was the engine broken in, I'm not getting into it but you dont want to baby a new engine. Mods?

Check your codes...

 

[GuNDeZZZ]

Check the ISC, my friends car did the same thing, ended up being his ISC.

 

[AbsoluteSpeed]

If it means anything the gas mileage is horrible right now.

Was the engine broken in, I'm not getting into it but you dont want to baby a new engine. Mods?

Stock tune .020" JE pistons-eagle rods-MHG and so on
I understand the whole hard and fast breakin and the shop had done almost a tank of gas worth of breakin before I got it.

 

[dumbo]

If it means anything the gas mileage is horrible right now.
Stock tune .020" JE pistons-eagle rods-MHG and so on
I understand the whole hard and fast breakin and the shop had done almost a tank of gas worth of breakin before I got it.

Its prolly fine then, I check codes,ect.

 

[87nasupra]

I personally DO NOT TRUST the "hard and fast " break in method....thats how a shop blew up an engine they built for me years back for my old 240. sounds like a misadjusted tps...my turbo was doing that right before the rebuild went underway

 

[hvyman]

hard and fast no more than 4k. if it was built right it wont blow up.

 

[GuNDeZZZ]

hard and fast no more than 4k. if it was built right it wont blow up.

Ugh, there are many ways to "break in a motor", just have to make sure the rings seat right, and you have no oil starvation and retorque everything.


The hard and fast way makes sense in a way, not in another.

My theory is let it go one heat cycle at low revs, and then use the hard fast without hitting redline method the second heat cycle, and then drive normally with oil changes in between and after.

 

[McGyvr]

I had the same thing after my rebuild. Never could find it until I stumbled across the codes. Adjusted the TPS and that was the end of it.

 

[IJ.]

"Hard and Fast" works only if EVERYTHING in the car is ready to do it, most times people have made multiple changes along with the fresh engine and there are usually bugs that will kill it hard and fast... :nono:

 

[grimreaper]

Breaking in a motor seems to me to be like asking "do aliens exists". Some shops say let it rev in N with varied rpms for XXX amount of time, others drive it like you stole it and others say drive it gently (and the internet just adds more opinions)... Id like to hear what our old timers do considering everything else is in top condition.

edit: other causes for motor damage were found.

 

[jetjock]

I break them in the hard way. Never had a problem.

Fwiw piston aviation engines (including turbo engines) are always done this way and they cost $25K just to rebuild. The engine is run for 1 minute to check for leaks. Since anything longer is detrimental the aircraft is then towed to the runway, the engine started, and an immediate departure follows. Thereafter the engine must be maintained at no less than 75% power until broken in. Many people use 100% power. To do otherwise voids the rebuilder's warranty and is just asking for either expensive repairs in the near future or, at minimum, a reduced service life. A new engine cost $60K and is broken in using the same procedure except it's done in test cell.