rattle & popping

[SlyAttacks]

I just picked up an 89 SikeKick with 84,000 miles. It runs great and passes its air check but it makes a strange fast popping sound from the throttle body (but not all the time) and the PVC valve rattles like crazy. It also idles a little high when it's cold and low when it's in gear.

Thanks for the help

[SlyAttacks]

More info? I just did the fallowing...
Spark Plugs
PCV Valve
Valve Lash Adjustment
Ignition Coil
Throttle Position Sensor
Oxygen Sensor
Coolant Temperature Sensor
Distributor cap and rotor

I picked it up from a friend for $300 and I want it to run perfect.

[jtgh]

popping back is a good sign for lean.
back fires thru TB .

pop , pop and then goes.

this is an 8v EFI TBI car.
it runs off the map and ECT, and IAT for mixture.
on this car it iat has lots of authority for mixuture unlike the cars with MAF sensors.
on this car air leaks cause, high idle and not lean.
id make sure map sensor hose is not clogged , and the nipple it connect to and manifold.
there is a filter on some that can clog.

if that is ok, you might be lean due to low fuel pressure.
fuel pump weak (not if you have full power cold)
also the Fuel filter clogged.
or fuel pressure regulator. sticking.

a quick test of the map, just pop off a tiny vac hose (like evap ) and see if rpm rises.
it if does, map is working good.

a sticking EGR might cause this too.

you got a heck of deal , and low miles too boot.

cheers.

[LongRod]

[quote=jtgh;139210]
"this is an 8v EFI TBI car.
it runs off the map and ECT, and IAT for mixture.
on this car it iat has lots of authority for mixuture unlike the cars with MAF sensors.
on this car air leaks cause, high idle and not lean.
id make sure map sensor hose is not clogged , and the nipple it connect to and manifold.
there is a filter on some that can clog."

OK so where is this MAP filter and can it be cleaned? If so what's the best method of cleaning? If not where's the best place to get a replacement filter?

[jtgh]

map is #18 , on firewall rear of TB.
17 is filter, just see if you can pass air thru it.

Id blow the air from map side , reversing flow and blasting any crap out.
it filters and buffers (smooths) the vacuum pulses to the map.

that popping sound.
assuming it is lean back fire. do you feel the loss of power as it hic ups?

hic pop , loss of power then resume full power.?

it sure sounds alike an intermittent problem.
that being the case, it could be sticking EGR main valve.
at what rpm (guessing) is the pop happening.
at idle , or only going fast, or only when I move my gas foot fast at any speed? (TPS creates rich transitions and if bad will prevent the rich transition and thus a short lean period during rapid right foot movements.
(the ecu actually monitor how aggressive your right foot demand is)


i would check fuel pressure and replace that fuel filter on suspicion.

one guy here had a fuel pump that only failed at 3500 rpm.
one weird pump. and only hot.?

http://carfix.stufftoread.com/INJECTORS/TBI-conn-1w.jpg


this leanness, if true , the important thing, is when it happens? and long in time and if it happens only above or below certain rpm's
this will lead to the answer, I hope.

cheers.

[SlyAttacks]

The popping is not a back fire. It pops many times a second and doesn’t affect the way it runs at all. It only does it around 1000 RPM, not higher or lower. The PVC valve is rattles like crazy at any RPM. I cleaned the MAP lines and filter. Did the tiny vac hose test but didn’t get a change in RPM, I removed a large vac hose and did. The fuel filter is new. I check the EGR valve with a vacuum pump and fuel pressure regulator but I still haven’t found the problem.

[jtgh]

sound can be hard to convey.
a compression test, to find a leaking intake valve that cause PCV to rattle?
you vacuum is all over the place.
a vacuum test at idle , 20 inch. HG. and solid, no wiggle allowed.
both are engine test fundimentals.

the popping is the exhaust blasting past a closed intake valve .(or it is sticking)
,or

you have a holed exhaust somewhere and you have muffer explosions.
nah, you said clearly it is induction.

cheers.
the vacuum test is 5 min test, put it on the EVAP nipple.
egr nipple is ported and zero at idle.

im talking about the intake manifold nipples. there.

cheers.

[SlyAttacks]

Maybe this will help? YouTube - SikeKick Sound

[jtgh]

i love it when folks rattle there you tubes.
i thinkyou need a new sound driver...... nah. just kid'n.


that is one wierd sounding motor. its coming out of the air horn huh?

unplug the iAC ,

could be lots of things.
besides a head valve intake.
it is seriously wrong. Mine just sucks and a whistle real high on top.
does it go away.
pinch some hoses, heck pinch them all 1 by one. even the brake booster. Vac hoses.only.

1 :iac bad.?
2: egr spring in side collasped and it just flops around. (feel it with finger, the diaphragm)
3: one guy here had a Lincoln cont. PCV valve installed and it did wierd stuff.
4: im think'n, hahahahah

fiddle all connected to intake ,leave nothing.


one guy had a bad TB gasket the fluttered side to side wierdly.

congrats you get the weird Kick award of the year,!!!

let fix this puppy.

cheers.

[kiradana]

i have the same motor and that same noise and have been trying to track it down for months, is it the iac. where is the iac. picture please