I've finally gotten my '86 back together with a new roller block, 74219 cam, and SuperRam (with Pro Topline heads). However, it's really running badly right now and I'm looking for suggestions on where to start.

1. I've not had experience with this cam before; I was told it would be a mild idle but honestly it feels like a street rod motor more than a normal engine. Is this right? At a stop light, at ~600 rpm idle, it shakes the whole car.

2. What would be a good starting point for the timing? It doesn't seem right anywhere near stock setting; it bucks when I give it gas in gear, and forget using overdrive... lurch, lurch, lurch. I feel timing is off, but did all I knew when installing everything to get it right. The car almost sounds like it's chugging until I get above 2500 RPM or so.

3. It stalls a lot until it gets warmed up, and even then it'll sometimes stall when I come to a stop (4+3 in neutral). I'm not using EGR (it's installed, but not feeding from the exhaust) but the guy (Jeff) who burned my chip said that wouldn't matter.

Help, please!

Thanks.
[RICHR]

 

Well, like any other major change, they'll be teething pains.

I'd first verify that all the sensors are at the correct settings.

Ignition timing with the EST disconnected; error code cleared after setting the timing by disconnecting the battery for at least 30 seconds. 6 degrees BTDC is the stock setting, but you may want to bump your to 8 to see if that improves the idle.

TPS voltage set to .54 (+/- .075) You may want to tweak that setting to .62 for better throttle response.

IAC counts in the 20 range.

Engine going closed loop; You can verify this with a ScanTool, Diacom or just by jumpering the ALDL and watching the speed of the flashes.

Put a vacuum gauge on the engine to verify that the vacuum is holding steady and not jumping up and down. If it's jumping you have a vacuum leak somewhere. Lots of water can track that down.

You should be seeing a vacuum reading of about 14" with the engine warmed up and idling.

The 219 probably isn't going to idle well at 600 RPMs. Was the PROM burned to raise the idle speed? I'd shoot for 800.

Check the MAF wires; the thin ones between the two screens (if yours still has screens) to make sure none is broken.

Lifter preload could be too tight on one or more rockers. This is copmmon problem and shows up frequently on the Forum. I posted a file in the Tech Tips Section on the procedure I recommend. Others have their favorite way - some like Pepsi, others like Coke.

Get back to us with the results and any other info you have.

Jake

 

Assuming that you have everything setup right, the stalling might be because you haven't got a looser torque converter and/or your IAC is not adjusted right. I 2ouled also get a looser TC. At least 500 above stock stall. Also, what are you using for fuel injectors? What are you using for an EPROM? I have had good luck with www.fasterproms.com in the past, They make a truely custom EPROM if you take the time to borrow their DIACOM to take datalogs and send it to them. With their DIACOM stuff, you can see what the ECM is doing.

I have run that cam before and it will not run right without proper EPROM settings. Timing is set a 6 deg and IAC is 20 counts and TPS is 0.54V. Also base idle is set up to at least 750

 

I've never worked with that cam either,but I have with cams of similar and greater duration on carbed vehicles.

Judging from the duration numbers of that cam, Part of the reason you're car is Ideling rough and shaking because it can't draw enough vacumm at 600rpm idle. Up that idle speed to about 800rpm to start with..

 

I have that cam, and I had my chip calibrated with an 850 RPM idle. It idles wonderfully, with a definite presence (you can easily tell its "cammed") Off-idle response is very good (although right now my timing is retarded by 2*, will be changing it to 8* or 6*). Vacuum is excellent at 16"!!

 

Ok. A followup. I reset the IAC and set the idle to somewhere between 750 and 800 (it jumps between 7 & 8 on the tach; I have no other way to check it). Also adjusted the TPS, which was at .76 - odd because I'd just set it not long ago (but before the mods started) when I got the new TB. Idle is MUCH improved, though the car still shakes (the prom was burned for 750, I found out today).

I only appear to have ~10 inches of vacuum with the gauge at the back of the intake plenum. It stays FAIRLY steady, but will dip to around 8.5 as the idle goes up and down. Vacuum leak? Almost all of the lines and connectors are new; some are OEM hard plastic lines and some are soft rubber hoses. I had one melt (!) on the left header during early tuning, so I added about 18" to its length and ran it around the battery. Won't melt THIS time! But the added length shouldn't affect anything, should it?

Fuel pressure is set around 40 PSI (it was 43 but I backed it down a tad). I still have the stock L98 injectors, but they were just cleaned and flow-matched. I shouldn't think they'd be a problem yet, though they might when I start hitting high RPMs.

How do you check the IAC count? Can't find that procedure in my shop manual. Also, how do you read the flash count after jumpering the ALDL (ports A and B, I presume) to check open loop? I know how to read the eprom codes, but that's it. I was letting the car warm up until coolant hit 200 and oil was around 160 - that was about 15 minutes of idle/rev/idle/rev.

I'll check the pushrod preload, though I was pretty happy with how they were set when I did them. A touch of looseness at full retraction and they don't *seem* to be making any noise. I'll check them again when I pull the valve covers off this weekend to try and clear up the last of the oil leaks.

Don't have a torque converter to worry about... just a worn-out old 4+3.

MAF was fine when I installed it and I can't imagine the wires have broken since...

Thanks for the help so far, guys!
[RICHR]

 

"[QUOTE=rrubel]Ok. A followup. I reset the IAC and set the idle to somewhere between 750 and 800 (it jumps between 7 & 8 on the tach; I have no other way to check it). Also adjusted the TPS, which was at .76 - odd because I'd just set it not long ago (but before the mods started) when I got the new TB. Idle is MUCH improved, though the car still shakes (the prom was burned for 750, I found out today). "

Since the PROM was burned for 750 RPM, then the flucuation between 7 and 8 isn't something to be concerned about; it's normal.

"I only appear to have ~10 inches of vacuum with the gauge at the back of the intake plenum. It stays FAIRLY steady, but will dip to around 8.5 as the idle goes up and down."

That may be a problem. The 219 should pull more vacuum than that. Fully warmed up and idling the engine vacuum should hold steady. If it doesn't, my first thought is a vacuum leak somewhere. Second thought is one lifter set too tightly.

"Vacuum leak? Almost all of the lines and connectors are new; some are OEM hard plastic lines and some are soft rubber hoses. I had one melt (!) on the left header during early tuning, so I added about 18" to its length and ran it around the battery. Won't melt THIS time! But the added length shouldn't affect anything, should it?"

No the longer hose won't cause a problem. There are several ways to detect a vacuum leak: unlit propane torch, spray carb/injector cleaner, etc. I just use plain old water from the garden hose. When the water hits the spot that's sucking air, the idle will NOTICABLY change and, perhaps, white smoke will come out the tail pipe when the water turns to steam.

"Fuel pressure is set around 40 PSI (it was 43 but I backed it down a tad). I still have the stock L98 injectors, but they were just cleaned and flow-matched. I shouldn't think they'd be a problem yet, though they might when I start hitting high RPMs."

You can always play with the pressure later down the road. 40 should be enough to give you a stable idle though.

"How do you check the IAC count? Can't find that procedure in my shop manual."

You'll need a ScanTool, Diacom or some other data logger to see the IAC counts.

"Also, how do you read the flash count after jumpering the ALDL (ports A and B, I presume) to check open loop?"

Jumpering the ALDL will cause the SES light to flash. How quickly the flashes occur indicates whether the system is in open or closed loop.

"I'll check the pushrod preload, though I was pretty happy with how they were set when I did them. A touch of looseness at full retraction and they don't *seem* to be making any noise. I'll check them again when I pull the valve covers off this weekend to try and clear up the last of the oil leaks."

I don't quite understand the "touch of looseness" part. Actually one setting that is too tight will cause a bad idle. There are different ways to set the lifter preload; engine idling or engine off. It doesn't take but ONE lifter set too tightly to cause a bad idle.

"MAF was fine when I installed it and I can't imagine the wires have broken since..."

Removing one plug and three clamps is all it takes to access the MAF wires to check them, just to be sure. If in doubt about the MAF, just borrow and swap in another one that you know is in good working order. Several of us have diagnosed a bad MAF by doing it that way.

Keep us posted.

Jake

 

My 219 cam idled extremely well with the stock ecm.(re-burned by LPE)

Around 850-900 rpm seemed best. And like the others mentioned, you could tell it was "cammed" by the un-even exhaust note we all know and love.

IMHO, that is THE CAM to have in a "hot" L98.(it propelled my car to almost 121 mph while driving it home each time from the track)

 

I'll check the vacuum again. However, since it was directly off the back of the plenum I tend to doubt a leak anywhere... unless the plenum itself was leaking.

I'll have to see if I can find one, then. I need something for logging some data for the chip guy as well.

So slow flashes are open loop and fast are closed?

I can just turn the pushrods and wiggle the rocker arms when the valves are closed. I did the manual-recommended 1@TDC/6@TDC method, but I think I'll do the engine-on/loosen/listen for rattling/tighten method next. I tightened each arm until I felt a bit of resistance and then did 1/2 turn further.

[RICHR]

 

My Corvette Shop manual lists the "quickness of the flash" procedure to determine if the system is closed loop or open. I've never had to resort to using it though, because I simply use Diacom to tell me which state the system is in.

So, I'll have to look it up to see if quicker flashes means open loop or closed loop. Don't want to give out bad info. Maybe someone who knows for sure can post and save me the trouble.

The vacuum leak, if there is one, could be:

Intake manifold to cylinder head
Lower Runner to Intake manifold
Upper Runner to plenum
TB to plenum
Accordian bellows between MAF and TB
Where injector(s) fit into the intake manifold
One of the TB plates (top and/or bottom)
Vacuum hose(s)
EGR valve
Brake booster; booster connections
Cruise Control hoses/bellows
Gas tank Vent hose
Hose nipple on underside of TB
Any of the other emissions hoses, etc.

I'm sure that others who are running the 219 will tell you, too, that cam should pull more than 10" of vacuum.

Jake

 

Groan... looks like my weekend is cut out for me.
Thanks.
[RICHR]

 

[RICHR]
The more I've read, the more I am leaning towards a vacuum leak. The SR is NOT a precision machined piece. The tops of my runnners were over .035" from flat/level relative to the plenum. Spent lots O' cash having it all machined, and Helicoiled to simplify the install, and avoid any leaks. I think that if you use the propane trick mentioned above, that you will likely find a leak somewhere on the intake. Good luck!

 

Be sure to keep us posted and let us know when you find the cause.

Jake

 

I will. I may have to give up (for time reasons) and take it to my mechanic. I need the car running right, soon. It was also pointed out to me that I didn't properly degree the cam when I installed it, which may account for some of the problems.
[RICHR]

 

Just sent you a e-mail. (The one in your profile).
Give me a call if you want to.

 

Mine ran like a pile of crap until I had a chip burned for it. Does the vacuum gauge bounce around, or does it just rise and fall with the idle? If it's fairly steady, except for idle fluctuations, I doubt you have a vacuum leak. Get a chip pronto.

 

If anyone's still listening on this thread, here's a brief followup...

I've had zero time to work on the thing the last couple weeks, so I took the car to my mechanic. The timing was definitely off, two teeth on the distributor. How I did that, I'm not sure... I bit the bullet and had him degree the cam again; he found it was one tooth off which isn't that bad and definitely wouldn't have contributed to the problems I have.

Then he told me that two cylinders were running REALLY lean and that there was a vacuum leak somewhere towards the back of the plenum, manifold, or similar. Hmmm... sound familiar?

Got it back home and shot carb cleaner around the manifold. It appears to be leaking around where the runners meet the manifold, but probably nowhere else. So I called Lingenfelter and asked for suggestions. I was asked if I'd put the runners on the proper sides. They're different??? Apparently so... there's minor machining differences and something about the EGR runner as well, according to Tim Dyer at LPE. He asked if I'd had any problems getting the PLENUM screwed on, and I said one bolt wouldn't line up so I just stuck it on an angle and used sealant on it. His response was that if the runners are on the wrong sides, every bolt but one will line up, and he told me which one wouldn't...

So if I can scrape together a couple hours then I'll swap the runners and *hopefully* that will take care of all remaining problems except for one... namely, how I'll be able to afford new rear tires every couple weeks .

Thanks for all the advice.
[RICHR]

 

Oh Yeah I've been following the thread. Sounds like a good place to start. Good Luck and continue to keep everybody posted. These are the types of threads where I gain a wealth of information

 

[SNIP=rrubel]If anyone's still listening on this thread, here's a brief followup...

"I bit the bullet and had him degree the cam again; he found it was one tooth off which isn't that bad and definitely wouldn't have contributed to the problems I have."

Oh Yes it is bad. If you installed the timing chain gear setup one tooth off that makes a tremendous difference in how the engine will run.

"Then he told me that two cylinders were running REALLY lean and that there was a vacuum leak somewhere towards the back of the plenum, manifold, or similar. Hmmm... sound familiar?"

TPI engines are VERY sensitive to vacuum leaks. Even a small leak will cause driveability problems. Remember, fuel and timing depend on info the MAF sends to the ECM which is measures as airflow passes through the MAF. If air is entering the system from some other point downstream of the MAF it is unmetered (the ECM doesn;t know it's there) and the fuel command sent by the ECM will be way off.

"Got it back home and shot carb cleaner around the manifold. It appears to be leaking around where the runners meet the manifold, but probably nowhere else. So I called Lingenfelter and asked for suggestions. I was asked if I'd put the runners on the proper sides. They're different??? Apparently so... there's minor machining differences and something about the EGR runner as well, according to Tim Dyer at LPE. He asked if I'd had any problems getting the PLENUM screwed on, and I said one bolt wouldn't line up so I just stuck it on an angle and used sealant on it. His response was that if the runners are on the wrong sides, every bolt but one will line up, and he told me which one wouldn't... "

You must also make sure you put the runner to plenum gaskets and runner to base gaskets on the correct side.

Thanks for all the advice.
[RICHR][/SNIP]

Jake

 

Funny thing is, according to the Crane Cams website installing the chain one tooth off will just move the power peak about 400 RPM up or down. Although I would expect more of a problem than that...

Heh. Yeah, I'm learning that one ...

Last time I thought I just matched the gaskets to the runners; I don't remember there being a difference except that you flip one over and it appears to match the other side. These things aren't labelled .

Thanks.
[RICHR]