Coyote not running right

[bobm488]

When slightly revving my Gen 2 Coyote the engine RPM’s comes down to a nice idle for 2 or 3 seconds then climbs up a couple of hundred RPM’s . It also stumbles a little bit when I rev it up. I have the GM type regulator/filter . I am pretty sure I have my plumbing correct, see attached picture.
Any suggestions will be appreciated.

120403

[initiator]

Have you double-checked the orientation of your mass airflow sensor? Not sure you'd see the nice idle at any time if it were reversed, though.

[michael everson]

Is the engine new or used? might check for a vacuum port open somewhere
Mike

[bobm488]

I checked the Mass Air sensor, it is in correct. It's a new motor from Forte. I don't here any vacuum leaks, but I'm a little hard of hearing

[Railroad]

Did it idle right at one time and now is not?
If this is what is going on from first start, and you can find no air leaks, you can try clocking the mass air meter tube.
Saying you have it at 9 o clock now, rotate it 90* at a time and see if things improve.
An air leak can be on your cold air tube. It does not have to be an intake or vacuum line leak.
Is your filter an oiled filter? With a straight shot from the filter to the mas meter, it might be possible for oil to get on the meter filament.
If this is on a warm engine, O2 sensors and or exhaust leaks cannot be ruled out.
Check fuel pressure, might disconnect vacuum line, cap on the engine side and see how it does.
If everything checks out, see if it has thrown a code. Also fan kicking on can cause the engine to speed up.
Let us know.

[lewma]

Did you calibrate your accelerator pedal ? I think the procedure is to turn the key one position, slowly depress and release the accelerator pedal 3 times, then turn the ignition off.

My Gen2 Coyote had a 'dead spot' when slowly accelerating but performing the calibration step cured the problem.

mark

[bobm488]

Thanks guys I'll try your suggestions. No I did not calibrate my accelerator pedal. It did have a fault code of P050A, cold start idle. Looks like I need to figure out what to do about this code.

[edwardb]

Symptoms associated with P050A are exactly what you describe in your first post. I don't have any experience with that one, so can't offer any advice. But definitely something to check further. With two Coyote installations, I've not had to do any kind of calibration or learning with the DBW pedal (accelerator). The engine won't stay running if the MAF sensor is installed backwards. It will start, but immediately shut down.

[wareaglescott]

Did you calibrate your accelerator pedal ? I think the procedure is to turn the key one position, slowly depress and release the accelerator pedal 3 times, then turn the ignition off.

My Gen2 Coyote had a 'dead spot' when slowly accelerating but performing the calibration step cured the problem.

mark

Never heard of that calibration either. Have a friend I keep in contact with that is a Ford engineer, used to work the ford performance tech line, I texted him after seeing this thread asking what he knew about the calibration of the pedal. He has never heard of that either.

[Railroad]

I think it is in the Gen I instructions. ,,,seems that is where I read it.

[GTBradley]

It might not make a big difference as both are vacuum, but it appears you have the CMCV vacuum line installed incorrectly. The coyote installation instructions have it connecting to the bottom fitting of the intake tube. See the red arrow I drew on your picture. The port just behind the throttle body (circled in red) can be capped/blocked off.

https://thefactoryfiveforum.com/attachment.php?attachmentid=120471&d=1578847629

It takes an extra length of vacuum hose - I think this was in my Coyote install kit that I bought from FFR.

https://thefactoryfiveforum.com/attachment.php?attachmentid=120473&d=1578847990

[bobm488]

It might not make a big difference as both are vacuum, but it appears you have the CMCV vacuum line installed incorrectly. The coyote installation instructions have it connecting to the bottom fitting of the intake tube. See the red arrow I drew on your picture. The port just behind the throttle body (circled in red) can be capped/blocked off.

https://thefactoryfiveforum.com/attachment.php?attachmentid=120471&d=1578847629

It takes an extra length of vacuum hose - I think this was in my Coyote install kit that I bought from FFR.

https://thefactoryfiveforum.com/attachment.php?attachmentid=120473&d=1578847990

Thanks, I've had it attached in both locations, surprisingly it makes no difference in how the engine runs.

[GTBradley]

Darn it! I hoped that would help. Anyway, if you need any other photos on how mine is hooked up, let me know. I'd be glad to help. The Gen2 Coyote lit right up and has run flawlessly for me ever since.

[bobm488]

I tried everything listed above; nothing seems to make a difference. The code has disappeared. This type of thing is why I was reluctant to go with a coyote vs. a simple SBF. I know when I get it figured out I will be happy I went with the coyote, just frustrated.
Thank you everyone for trying to help.

[edwardb]

I tried everything listed above; nothing seems to make a difference. The code has disappeared. This type of thing is why I was reluctant to go with a coyote vs. a simple SBF. I know when I get it figured out I will be happy I went with the coyote, just frustrated.
Thank you everyone for trying to help.

Don't give up. You'll love the Coyote. Had both and no comparison IMO. This forum is full of issues with SBF's too. I know, doesn't help or make you feel any better right now. But they're not immune either. Two thoughts. (1) Have you thought about installing a pressure gauge on your fuel line? Many have used the GM regulator, although I haven't. Would be good to confirm you're getting the proper pressure at the inlet on the engine. (2) Even though they run OK on the standard tune, I always recommend a Coyote installation should plan (and budget...) for a custom tune. Mine was done by Lund and made a big difference. I'd suggest it regardless, but the tuning process likely would also uncover any other issues.

[Paul2STL]

Do you have a 3 1/2" plastic MAF tub inside the 4" aluminum tube around the MAF? If you do you may have it in back words? I accidently put mine in back words when I took it off to clean one time, MAF was in the correct position, but the inner adaptor tube was wrong. If I remember correctly it ran but stumbled. Something else to check out.

[bobm488]

Paul2STL
My MAF tube is 3.5", so no inner tube is required. Thanks
Edwardb
I did plan on doing a tune to get it dialed in. I will look into the pressure gauge, Thanks