Noob needing help, not building boost and backfire

[TurboBuRick]

Thanks for the advice, I have now checked the plugs (broke one so I replaced them all to be safe), wires are new magnacores, coil and ignition I dont have spares of to test...

I have checked the IC hoses and they look good, cant get to the IC until I get home (at my Grandparents now). Fuel seems ok.

It runs just fine at part throttle, whether cold start or hot, the problem seems independent of temperature.

Yeah, I'll keep checking the small stuff until only the hard stuff is left, wouldn't do to change the cam or head gasket and get it all back together to only have the same problem lol.

Bottom line for tonight is that under light load and idle the BLMs are 110, when I get over about 1/3-1/2 throttle or about 95 on the L8 load indicator on the scanmaster the BLMs go through the roof into the 144 range. It seems like as I get to that breakpoint there is a miss which is causing it to read lean and run poorly.

Any other ideas given those symptoms?

Plugs all looked the same? Where any of them dark?

The way to check the cam is pull the valve covers and unhook the plug on the side of the coil/module. Unhooking the coil so car won't start. Now you have someone turn the motor over and whach the rocker arms. If you have a flat lobe on the cam you will have a rocker that is not moving like the others.
No guessing here, it will be quite obvious. Good Luck

One other thing. I really don't think it's the IC or hoses leaking because your bl would drop not raise in that condition and it would'nt miss just bog.

 

[Lee_Burough]

One more thing to check would be loose grounds. One I had a problem with is the coil pack. Make sure it is bolted down tight if its loose it will cause strange behavior also.

Cleaning and tightening the grounds is a good idea too (the back of the heads and where they connect at the firewall)

Have you ever driven a carburated car with a bad accelerator pump? Whenever you increase the throttle position under load, it breaks up and misses....I had a similar symptom the day I had to drive a TTA home with a MAF disconnected. A similar power symptom, with no popping....

When you've done everything you know to do, and before you drive back home, try this simple MAF test: With the car idling at operating temp, use a screw driver handle and tap the MAF gently. If the idle RPM changes suddenly, you have bad MAF.

If you ever find some parts to swap out, meaning contact somebody (TB.com, GNTTYPE.org, TBS.com boardmembers) in your locale with spare parts, try swapping out the MAF as well as the coil/ignition module. Where do your grandparents live? Maybe you could post here for help from a local board member...Its probably one in 50 chance, but, you could get lucky.

With a scanmaster, you should be able to adjust the IAC by using THIS site, or the trouble shooting sections of Steve Wood's site. Good Luck.

 

[SloGN]

Bad MaF

Sounds to me like the MAF is taking a crap. as airflow increases the MAF signals the ecms to add more fuel.

Drive the car and watch the AF #'s as it starts to build boost. the poping and stuttering it is slowly running out of fuel case the MAF is craping out on the bigger end of the scale. Idle and part throttle cruising AF #'s are below 50 in most cases.

 

[TurboBuRick]

Any luck?

 

[Scott Atk]

Start the car. Unplug the cam sensor with the car running. Take it for a rip and report back.

 

[wile2k]

Well, I'm kinda waiting to have it fully resolved before I report back.

I'll know more this weekend when I really get the chance to tear into it. I'm going to pull the plugs again and check for any deficiant cylinders and go hunting for exhaust leaks before the turbo.

With the high BLMs only at medium+ engine loads, it seems like a cyl is dumping the air/fuel mixture without burning it, or I have a huge exhaust leak (which I can't hear).

I can make full boost if I keep my foot in it long enough, it just comes on very slow (car running very rich as well).

I'll know more this weekend and make sure that this post isn't neglected.

 

[D's GN]

Sounds exactly like a problem I had awhile back, Coilpack or Ignition module...any buddies around that would lend you them to test. Only takes a few minutes to swap.

 

[wile2k]

Ok, to update. I finally got over being in denial and took off the valve covers. Rick... you da man... #3 flat intake and exhaust lobes. Good time for a roller setup I guess. I'm going to change the head gaskets while I have it all apart.

I tried about everything before admitting defeat. At least I guess I know the car better though and I'll know it even better after I pull it all apart lol.

Thanks for all the help guys, great community that I find myself in.

 

[TurboBuRick]

When you said poping in your first post, that sums it up for me. Well now you know. Roller would get rid of that problem. Good Luck. O ya and make sure and do the headgaskets. Flat cam and blown headgaskets go hand and hand.