5.0 EFI engine backfire

[agboy91]

Hello, need few suggestions on and engine backfire/misfire issue that has developed in my 5.0 swap. When I lug the engine down, it had a engine backfire (reminds me of a Vapor lock). It runs seemingly fine under normal loads but sputters andnbackfires like the timing os off when under a load or when I shift to 4th and lug it a bit. I have checked the firing order and plug wires and all seem fine. I am getting fire to each plug but I have not pulled the plugs to see if they are firing. I just seems to be misfiring and sputtering in the engine. Any help in pointing in the right direction is appreciated. Thanks in advance. Btw, I have a 2000 explorer 5.0, no cam with a M5OD.

 

[FrankSG]

Hello, need few suggestions on and engine backfire/misfire issue that has developed in my 5.0 swap. When I lug the engine down, it had a engine backfire (reminds me of a Vapor lock). It runs seemingly fine under normal loads but sputters andnbackfires like the timing os off when under a load or when I shift to 4th and lug it a bit. I have checked the firing order and plug wires and all seem fine. I am getting fire to each plug but I have not pulled the plugs to see if they are firing. I just seems to be misfiring and sputtering in the engine. Any help in pointing in the right direction is appreciated. Thanks in advance. Btw, I have a 2000 explorer 5.0, no cam with a M5OD.

Check for a vacuum leak. I had a similar issue last year, and it took me a long time to figure out where the leak was coming from. Also when you set the timing make sure that you have the sprout clip removed to set the timing at base 10.

 

[Viperwolf1]

You need to see what the fuel pressure is doing when it happens.

 

[needsmoarturbo]

You need to see what the fuel pressure is doing when it happens.

Yes, I would look at fuel pressure too. Sounds like it could be a problem

Sent from my Moto G (5) Plus using Tapatalk

 

[agboy91]

Thanks I'll check both out tomorrow. Would any of these issues through a code? My MFi light is not on but it may not be picking it up. Thx.

 

[EFI Guy]

It takes quite a while for a misfire code to appear indicating a cylinder. Get yourself an ELM327 dongle and Forscan if you haven't already. Some computers will show misfire counters per cylinder in real time. If yours doesn't, you can still isolate it to the offending bank by watching short term fuel trims. They will briefly spike lean when there is a miss on that bank.

edit: To add to that, watching long term fuel trims can help you decide if there is a vacuum leak. If long terms show lean at idle but get considerably better with RPM, you probably have a vacuum leak. If it continues to show lean at higher RPM then it's usually a dirty/bad MAF.

 

[gavindg]

If its a popping sound, check the O2 sensor

 

[agboy91]

Thanks EFI guy. I see a forscan lite on the ap store. Is that what you are talking about? Also, Can you send me your form, I have another Computer to flash.

Gavindg, how do I check the O2 sensors? Thanks.

 

[EFI Guy]

Yes, the lite versions are for smart phones. There is also a Windows PC version that is free and has some handy features that the lite versions don't. When you buy your ELM dongle, make sure that it supports the J1850PWM protocol. A lot of the cheap ones sold currently do not.

 

[gavindg]

Gavindg, how do I check the O2 sensors? Thanks.[/QUOTE]

The Scan should catch it.
Mine also did the same as yours when the fuel filter was plugged. If its been a while, replace it for a quick check.

 

[agboy91]

Ok is there a trick to the elm? I have a wifi one plugged in, the red power light is on and when I First plug it in, the OBD and the PC lights come on then go off. Is this normal? . When I search for wifi on the forscan, it say elm not foind. Any suggestions on the best elm for iPad/windows? I plan to download the pc version tomorrow.

I ran the bronco around today prepping for an Atlanta bronco get together Sunday and it still occasionally sounds like a Johnny Popper if you know what that means. I checked the vac ports and all either had a hose or were plugged. I plan to change the fuel filter tomorrow as it's the original explorer filter but it seems to be getting fuel but seems to only be running or 6 or 7 cylinders. More diagnostics tomorrow. Thx

 

[Skiddy]

Gavindg, how do I check the O2 sensors? Thanks.

The Scan should catch it.
Mine also did the same as yours when the fuel filter was plugged. If its been a while, replace it for a quick check.[/QUOTE]

same here with the fuel filter many times finally dropped the tank and cleaned it

 

[EFI Guy]

Ok is there a trick to the elm? I have a wifi one plugged in, the red power light is on and when I First plug it in, the OBD and the PC lights come on then go off. Is this normal? . When I search for wifi on the forscan, it say elm not foind. Any suggestions on the best elm for iPad/windows? I plan to download the pc version tomorrow.

I can't help much with IOS, I assume you probably need to set a static IP in the settings for it, but I could be wrong.

There was some discussion on higher end ELM units here:
http://classicbroncos.com/forums/showthread.php?t=272318

If they got Forscan to work well with the KIWI unit it would be the way to go, PLX makes decent stuff. If not then I'd try the OBDlink unit listed in that thread.

 

[gavindg]

Ok is there a trick to the elm? I have a wifi one plugged in, the red power light is on and when I First plug it in, the OBD and the PC lights come on then go off. Is this normal? . When I search for wifi on the forscan, it say elm not foind. Any suggestions on the best elm for iPad/windows? I plan to download the pc version tomorrow.

I ran the bronco around today prepping for an Atlanta bronco get together Sunday and it still occasionally sounds like a Johnny Popper if you know what that means. I checked the vac ports and all either had a hose or were plugged. I plan to change the fuel filter tomorrow as it's the original explorer filter but it seems to be getting fuel but seems to only be running or 6 or 7 cylinders. More diagnostics tomorrow. Thx

And thats why this one is alot easier to use (usually..)
https://www.amazon.com/gp/product/B000EW0KHW/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

 

[agboy91]

Thanks but I have OBDII.

 

[Titan34]

Ok, I got my new ELM in the mail and an now able to communicate with Forscan. Here are the codes I am getting.P1000, B1600, U1262,P0304, P0305, P0743, P0750, P0755, P1460. Not sure why I'm getting 743, 750, & 755 as I have a manual trans. Does 304 & 305 mean I have bad or plugged injectors? Any help is appreciated.

 

[Titan34]

This is Agboy91 btw. I guess I,was logged in under my sons account. Thx.

 

[EFI Guy]

P0304 and P0305 indicate that cyl numbers 4 and 5 are misfiring. Check the plugs, wires, and listen to the injectors with a stethoscope for starters.

P1000, and P1460 are to be expected. You should not be getting the B or U codes unless this is still installed in the Explorer? Those codes are usually generated by the GEM module.

You should also not be getting any trans codes, I'm showing the tune is set up for a M/T and it looks good from what I see. If those continue to pop up after you've figured out the rest of it then send the PCM back for me to check it out.

 

[agboy91]

Ok, here's and update. It's still misfiring. I have checked plugs and wires and all seem to be OK. I started it with plugs 4&5 removed, one at a time and had fire to the plugs. One thing I should mention is I'm running EVAP on my truck but forgot I didn't connect the tube from the tank to the EVAP unit, I guess this could be causing the vacuum leak if it operates while I'm driving. I don't really know if it operates while driving or just at start-up. I have not used a stethoscope on the injectors yet but I don't see and faults when I view them using FORScan. I saved my recordings but don't see how I can upload them here. Let me know if you think the EVAP could be causing the misfires. Thanks.

 

[agboy91]

Bringing this back up as I still have the engine backfire issue. Could this be a vacuum leak that would cause the timing not to advance/retard. I’m not sure if the timing is advanced with vacuum on the expoler 5.0 or if its electronically controlled by the PCM. The more I drive it, seems to be a timing issue as it runs fine unless under a load like going up a hil in 3rd or 4th gear. . Any pointer is appreciated. Thx.