Joey Mitchell

First off, I'm not tryna blow up these forums guys, I guess my car just has a lot of f**king issues. Yes I do plan on a swap soon, but until then I'd like my y7 to run as good as it can. Ok, now on to the issue.

My y7 is backfiring between gears, when I let off the throttle completely and disengage the clutch. It's not a real loud backfire, in fact I prob wouldn't hear it if my exhaust wasn't so loud . I kinda think it's due to my timing being set without a timing gun, because I don't have a timing gun... Could placement of the dizzy cause this issue? Is there a way to get my timing close without à gun? What else could cause this slight backfire?

Joey Mitchell

Come to think of it, and this is an issue I've been meaning to mention for a while, I couldn't set time with a timing gun anyway. I don't think my harmonic balancer is stock. Harmonic balancer for that year model is supposed to have one white mark for tdc, but mine has 3 marks together and then a mark by itself off to the right. Tdc doesn't line up on any of the marks through the gun sights on the timing belt cover, instead tdc is somewhere in between the marks.

I bought the car swapped, the car is a 98 ex, previous owner put a y7 in. I've found all kinds of janky work done to it, but this one boggles me. Aside from marks on harmonic balancer not lining up, part of the ps belt grooves are broken off of it.. idk idw my ps belt stays on tbh. So is my harmonic balancer off of be an eg or something? How can I set ignition timing like this even if I had a timing gun? Find tdc and make my own mark on the hb?

White_EG1

tony_2018

Mark to the far right IS THE TDC MARK. Just put some whiteout on it.

mk378

It's possible someone put the pulley on without the key. Yes you can find TDC by removing spark plug 1 and probing the top of the piston then make your own marks.

Also check the TPS calibration. The ECU is programmed to turns off all fuel to the engine when (a) rpm is above idle speed and (b) TPS reads zero. This would be the case when you shift gears. If it keeps putting fuel in while shifting gears that tends to find its way to the exhaust and then explode.

Joey Mitchell

The harmonic balancer does have the woodruff key in it, I just put a timing belt on it. When I put the belt on it I found tdc by the lining the mark on the crank to the arrow on the block, and double checked it by pulling 1st cylinder plug and putting an extension on top of the piston. After doing a little research I'm pretty sure they put a harmonic balancer on it from either a y8 or z6 bc the timing marks are different than those from a y7.

I don't notice any loss of acceperation, however I do need to purchase a multimeter and calibrate the tps bc I changed it out about a week ago and wasn't able to calibrate it. I'm honestly not sure when the car started doing this little backfire or how long it's been going on. I do however suspect the car is running rich because I smell gas fumes from time to time. I'll get a multimeter and calibrate my tps as soon as possible.

A question I've asked myself a million times, is there any point in even worrying about ignition timing to begin with? I've read and seen in videos where when u set it you have to pull a fuse bc if it is off any the ecu will just correct it. If the ecu is just going to correct it anyway what would be the point in using a gun to set ignition timing?

tony_2018

ecu doesn't do everything...

mk378

At idle the ECU changes the timing in conjunction with the idle air control valve to stabilize the idle speed. Changing the timing is a lot faster than the air control valve. While driving though, it uses a pre-set advance curve which requires the mechanical "base" timing to be correct. Thus there are slotted holes on the distributor to make it adjustable.

Before setting the timing it is essential to install the ECU test jumper which prevents the ECU from making timing changes, then you are looking at the "base" spark timing. When the test jumper has been recognized, the CEL will light up steady.