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86 2.8 Feels Anemic, Wants to Stall When Cold? by nmkaufman
Started on: 04-10-2015 08:10 AM
Replies: 5 (154 views)
Last post by: nmkaufman on 04-14-2015 08:33 AM
nmkaufman
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Report this Post04-10-2015 08:10 AM Click Here to See the Profile for nmkaufmanClick Here to Email nmkaufmanSend a Private Message to nmkaufmanEdit/Delete MessageReply w/QuoteDirect Link to This Post
Greetings, Fiero gurus.

I recently acquired an 86 GT, 4-speed muncie with ~120k miles.

The car ran fine for the first 3k or so miles, but had a loud exhaust leak from the rear (thank god) exhaust, and had the egr, cruise control, and EVAP cannisters deleted by the previous owner.

I was already getting pretty decent fuel economy (~25mpg 80% highway) but wanted a bit more due to my long commute, so set off to fix the EGR.

Here's a total list of things I've done leading to the current problem.

- Replaced the EGR hose with a Rodney Dickman piece, which involved
> removing intake plenum
> removing distributor
> removing throttle body (left it connected to those giant coolant lines)
- Replaced the cap and rotor (they looked like they had been to the bottom of the sea.)
- Replaced the PCV (for good measure)
- Cleaned / Reconnected EGR Solenoid (it turned out to be dirt / corrosion on the differential pressure / feedback sensor)
- Ran new vacuum lines to the EGR Solenoid / Valve
- Reconnected Cruise control (it was just physically disconnected from the throttle body....? I'm beginning not to trust the PO's mechanic)
- Ran new vacuum lines to the cruise / EVAP cannister
- Replaced the rear (trunk side) exhaust manifold gasket (required drilling out 3 broken bolts!!! Love this car!)
- Checked my base timing and while I was poking around in there advanced it by 1-2 degrees average between cylinders 1 & 4 (around 10 IIRC) in diagnostic mode
- Reset the computer

I still have a MINOR (certainly not enough to do anything about it,) exhaust leak on the firewall side, but now my cruise (and assuming EVAP) works, no more code 32, and my fuel economy has increased by nearly 3mpg average!

But when the car is cold the car feels very anemic, and wants to die when starting from a stop, unless I hold the RPM's higher and feather it, which I never had to do before.

After a few minutes (I'm guessing when the O2 sensor takes over) it stops, but still surges a bit in low gears at low speed (it did this before, to a lesser extent.)

Warm, it still idles right around 1,000 on the dial, exactly the same as before the repairs.

I know I screwed up by replacing so much stuff at once, but can anyone narrow down something I might check out first? Does it sound like a vanilla vacuum leak somewhere? EGR stuck open? Timing too advanced?

I swore up and down I was going to stop working on the car until something serious happened after the whole exhaust debacle, but I just want to make sure I'm not damaging the car by running it super lean or anything.

Does this sound like anything I should worry about, or wait for it to get worse / undriveable? And are there any easy (free) things for me to rule out?

Thanks guys!

[This message has been edited by nmkaufman (edited 04-10-2015).]

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Gall757
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Report this Post04-10-2015 10:25 AM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Welcome to the Forum!

If your car was running super-lean, it would tell you...so I would drive it. You have not mentioned the IAC, which may be why it does not idle well. Check for dirt or a bad connector.

If the PO closed off the EGR system properly, he changed the computer chip also. It's unlikely that this happened, but its possible.
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Report this Post04-10-2015 10:49 AM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
"Ran new vacuum lines to the cruise / EVAP cannister"
Make sure EVAP lines go to correct vac ports.

Disconnect cruise vac can from metal tube to engine... The can likes to rust and even small holes are a problem.
Check for vac leaks everywhere. See my Cave, Vac Leaks

Get another tach... don't trust dash tach.
ECM scanner can help but scanner active then idle RPM will changes... Scanner should show 1000rpm at idle. Normal idle w/o scanner is ~900rpm.

 
quote
Originally posted by Gall757:
If the PO closed off the EGR system properly, he changed the computer chip also. It's unlikely that this happened, but its possible.

If had DTC 32 then likely did not change the PROM.

No EGR might change Ignition timing. Check timing.

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nmkaufman
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Report this Post04-10-2015 12:24 PM Click Here to See the Profile for nmkaufmanClick Here to Email nmkaufmanSend a Private Message to nmkaufmanEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Gall757:If the PO closed off the EGR system properly, he changed the computer chip also. It's unlikely that this happened, but its possible.


Unfortunately, that's not the case! I was getting a code 32 everyday on my way home from work, usually as soon as the coolant reached operating temperature, sometimes delayed.

I suspect the pipe was just leaking so they took it off and capped it. It ran fine, I'm just chasing fuel economy.

Funny enough, when I got the car, it had a marginal thermostat that would only allow the coolant to reach a hair UNDER normal temperature, so I suspect the previous owner may have never even known there was a code.

 
quote
Originally posted by theogre:Disconnect cruise vac can from metal tube to engine... The can likes to rust and even small holes are a problem.
Check for vac leaks everywhere. See my Cave, Vac Leaks


I will start plugging vacuum hoses after work, and reconnect them one at a time.

 
quote
Originally posted by theogre:Get another tach... don't trust dash tach.


I'm not worried about the idle being high, etc. I'm just using it as a baseline, ie. it's not idling any higher/worse than it was before. I read how they can be inaccurate by ~100rpm or so.

 
quote
Originally posted by theogre:No EGR might change Ignition timing. Check timing.


I will check timing, as well. The timing was actually a bit retarded when I checked it, so maybe reconnecting EGR has reversed this and it's now super advanced.

 
quote
Originally posted by Gall757:Welcome to the Forum!


Thank you! This place is a great resource.

I will report back.

[This message has been edited by nmkaufman (edited 04-10-2015).]

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nmkaufman
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Report this Post04-10-2015 08:59 PM Click Here to See the Profile for nmkaufmanClick Here to Email nmkaufmanSend a Private Message to nmkaufmanEdit/Delete MessageReply w/QuoteDirect Link to This Post
So, I capped off the vacuum lines going to the EGR and cruise / EVAP and that didn't help any, so I hit it with the timing light.

Timing was a bit higher than I remembered setting it, but then I remembered that with the old cap and rotor I was getting a lot of 'slop' and it was hard to set the timing accurately. The mark seemed to jump around a lot, must have been a lot of arcing and crosstalk happening, because tonight it was rock steady.

I backed the timing off from a hair over 12 to the stock 10, and shortened my soft vacuum lines as much as possible.

I'm thinking that now that I have the pressure differential sensor on the EGR solenoid working, the car may not like the extra advance it's giving it. You may have hit the nail on the head, there.

I won't know if I fixed my original problem until the engine cools overnight, but it did run very nice and smooth on the way home. It may have been wishful thinking / placebo / sheer coincidence (it was a cool evening,) but a lot of that hesitation and jerkiness I was getting at slow speeds seemed to be gone.

I'll let you know if it sticks, but I think it's a step in the right direction.

[This message has been edited by nmkaufman (edited 04-10-2015).]

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nmkaufman
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Report this Post04-14-2015 08:33 AM Click Here to See the Profile for nmkaufmanClick Here to Email nmkaufmanSend a Private Message to nmkaufmanEdit/Delete MessageReply w/QuoteDirect Link to This Post
Well, nothing I've done has made any difference so far.

I'm suspecting a vacuum leak beneath the intake plenum, but I won't be able to do anything about it for a few days. I need to order the gasket, and I can't currently open my trunk.

And that thing you're thinking of right now, I've already tried that! I think there's a wire actually disconnected in the back.
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