Idle question but not the same old.

[18lbs]

First my car,
84 with 86 computer, brown tops, FMIC, A237 cam, 3" exhaust into duals, engine and turbo pretty fresh. I bought the car put together and drive it about 1000 miles or so a year for the last 3 years. I am a bit hesitant to screw with it because overall it runs great. Starts immediately boosts fine to 18 lbs. Okay here's the question.

At idle it has always had a lope. Kind of like in the old days when you had a high lift cam. Would you say this is 'normal' given my set up or is this a TPS issue?

Second question, cam has an adjustable sprocket. Plus or minus 10. It is straight up right now and makes absolutely no power until minimum 3000 rpm. Since I don't run the crap out of it, would it be worthwhile to adjust the cam to move the powerband down a bit.

I had to repeat though I kinda don't want to mess with it too much because overall it has never let me down.

Thanks for any thoughts.

Rick

[Patrick]

Sometimes in a nearly stock engine, a "lope" can be confused with the O2 sensor doing it's thing after the engine has warmed up. Upon reaching closed loop, the O2 sensor takes over and can appear to be acting like a lope.

[18lbs]

It does the same thing, hot, cold or in between.

[SVOTim]

My 86 has always had the lope, sometimes dipping down to a shutter, then back to a lope, but is runs balls out and I beat the hell out of it on the autocross... It's all good. I think the PE has a bit to due with it.

[MikeFleming]

What cam does it have? That can make a big difference on whether moving the cam centerline will have much effect on low RPM power. Most cams in these engines - especially with the 84 0.63 turbine housing - don't do very much below 3K.

First off, find and fix any/all intake system air leaks.

Last resort - raise the idle 100 RPM higher.

As far as TPS setting, do you have an advance type timing light?

[18lbs]

What cam does it have? That can make a big difference on whether moving the cam centerline will have much effect on low RPM power. Most cams in these engines - especially with the 84 0.63 turbine housing - don't do very much below 3K.

First off, find and fix any/all intake system air leaks.

Last resort - raise the idle 100 RPM higher.

As far as TPS setting, do you have an advance type timing light?

Its the A237 cam, honestly not sure what turbo, PO blew it up running a hybrid. Yes on the timing light. Other than everywhere any likely culprits for vacuum leaks.

[MikeFleming]

You ain't gonna get the low end power you want with that cam. We can let Bo speak about cams since he's our resident expert.

Yes, most vacuum leaks are under the hood - but sometimes can get under the dash too. We need to start a thread on chasing and fixing vacuum leaks.

You should be able to look at the turbo and see what sized turbine housing it has. or snap and post some pics.

You can use your timing light to see where your TPS is set. Get a base reading with engine idling, closed throttle. Using a PE EEC (86 SVO) with base timing set to 10, you should see approx 30 degrees BTDC (hence the advance type timing light). Then open the throttle ever so slightly - not enough toe raise the RPM, just anough to move th TPS value a wee bit higher - while watching the timing mark.

As soon as the EEC detects TPS movement into the Part Throttle (PT) range, the timing mark will advance ~15 degrees. The trick is to set the TPS so it doesn't false trigger - especially with a worm throttle plate and shaft (old tb housing). Note that at any RPM with closed throttle (CT) the timing will immediately return to the 30 value. If the timing is wandering around, then something is not right. It should drop to the 30 value immediately whenever the throttle is closed.

[Stinger]

You ain't gonna get the low end power you want with that cam. We can let Bo speak about cams since he's our resident expert.

Agreed. Furthermore, the A237 is known to lope at idle so I'm sure that's the cause of yours. The A237 is kind of an "all show, no go" cam. It sounds good, it feels good, but when you put it on a dyno or run it at the track, it just doesn't show the gains it should.

[18lbs]

Okay so if I were to dirty my hands with a cam change only, what should I look for? Ranger roller? I have two used heads with cams on them any way to id what they are?

[MikeFleming]

The RR ihas a smooth idle and probably the best low-RPM smoothness of what's available for the 2.3. However that's where it all ends. it has a very narrow, low-RPM power band and there's just nothing exciting or performance enhancing to come out of a stock cam designed for a light truck.

If you're lucky (heavy on the "if") there will be some numbers stamped on the end of the cam(s) you have that ID it. However the only sure way to know is to get a fixed lifter, fresh rocker, a degree wheel and a dial indicator. And an hour or so. Are the spares roller cams?

Or you can contact Bo and ask about his cam kits.

[18lbs]

Thanks, I'll check the cams in daylight, they are rollers.

[Stinger]

Or you can contact o and ask about his cam kits.

And by o he means Bo ;)

[Raven855]

i think the Boport 1.5 cam walks all over the ranger cam. My favorite is the 2.1 cam though

[GLASSMAN]

The ranger roller cam in my 85 with the big valve head and 3"exhaust doesnt turn on till rite at 3000rpm. Or atleast thats when the motor comes alive.

[MikeFleming]

And by o he means Bo ;) Thanks for the correction, stinger. I edited the original post.

[18lbs]

Thank god that got sorted out. I was just sending an email to Oprah asking about 2.3 cams.

[MikeFleming]

Okay so if I were to dirty my hands with a cam change only, ... It isn't necessary to get your hands dirty just doing a cam change. Clean the engine first.


I was just sending an email to Oprah asking about 2.3 cams. She's more into house refurbishing than car restoration.

[Stinger]

The ranger roller cam in my 85 with the big valve head and 3"exhaust doesnt turn on till rite at 3000rpm. Or atleast thats when the motor comes alive.

That's typically a result of when you reach max boost (peak tq) more than the cam.

[Chalky]

i think the Boport 1.5 cam walks all over the ranger cam. My favorite is the 2.1 cam though

Tony, i'd be interested to read your thoughts and comparisons of the various cams. I have the 1.5 but drove the "Road Warrior" with a 2.1 and it pulled hard!!!!