7 replies to this topic

[06/85-Si]

Hi guys my Si starts fine idles fine but when i throttle the car it back fires slightly and when i let of the throttle it sputters a bit I just got the car running but I'm not familiar with the vacuum.system and what i find online is minimal. Is there any deletes i can do with the vacuum.system i got a video too

[1985 CRX SI]

I would start here:
http://www.redpepper...1b/aaa.png.html
Jeff

[anjin]

PGMFI is pretty robust really. So as well as the vacuum lines and making sure connections are good, I would do some basic checks around timing, including the timing belt.  Easy to be a tooth off on intake or exhaust, and it does nasty things to on-throttle behaviour. Vacuum lines and Timing belt would be quite early on my personal check list - I've worn those two t-shirts a number of times.

[06/85-Si]

Well the timing is good triple checked and the vacuum system is all correctly hooked up I've changed the cap rotor plugs wires fuel filters and still getting backfire as soon as load gets on the engine real rich smelling kinda blueish smoke idles great except shuddering a little so I want to change fuel regulator injectors and the vacuum advance but all that's spendy any suggestions

[millcreek]

I can tell ya this.... if the car is idles good then your fuel injectors are ok....
You can test the regulator but you'll need a fuel pressure gauge....
Even a bad vacuum advance will not cause the problems your having....

It sounds like you have a timing issue....check the mechanical advance in the distributor....it should move freely and spring back....

Can you rev the car?? Will it get past the "backfire" and hold at a higher rpm?

Wish I could be more help...ya got some strange stuff going on.....

Good luck.....Mark...

[millcreek]

You say you just got the car running....how long has it been sitting?? How old is the fuel??
Contaminated fuel.....

I've seen it a few times....

[06/85-Si]

Fuels new but i haven't checked internals of dist thanks for the pointers yeah the fuels all good probably timming thanks vuys when i get it goung i'll post some pics

[Mark L]

What is the history?

Was this a known good running car and developed a problem, or is this the way you picked it up?

The engine is 30 year old. First thing I would do is a compression check and/or a leakdown check.

Also, I would use a vacuum gauge to see if you have a steady 18-21 at idle.

 

Mark