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Discussion Starter #1 (Edited)
I keep working on my 86 after car was a non-runner, but I still have some issues that need to be addressed:

The car bucks on first unless I go really easy on gas pedal. I would think this could be the transmission rear mount, the engine ones or all 3 of them. There is a hint the engine moves a lot since there is a mark from the radiator cap on the inner surface of the hood that leads me to think the engine is bucking, but I'm not completely sure about that.
It also shimmies and overreacts to road irregularities and I know this is not a balancing issue since I rebalanced all 4 wheels, but I am also assuming this could be due to cheap tires with a criss-cross patern that got squared due to years parked in the garage with tires slightly deflated in the same position. (I already got new tires and plan to mount them soon, but still, this could be shock absorbers or something else, but I checked suspension, particularly ball joints, but as far as I can tell, they are OK but not in excellent shape.
Transmission shifts fine, but there is a slight vibration when one releases clutch pedal and I feel a slight slippage so I am assuming clutch it's going bad, and also rear engine seal seems to be leaking, same as pinion seal on differential, so I will have to remove tranny and because starter driver is also beginning to fail, the best thing to do is to get tranny out and maybe go crazy and replace guibo, middle bearing and support and maybe universal joints.
I just wanted you all's valuable imput first, because I wanted to make sure the bucking issue is related to mounts or maybe something entirely different.
I want to install a pre-74 manifold, to replace catalytic convertor (I am assuming if the lambda sensor is disconnected computer will go to limb mode and slightly enrich mix?) and get a free flow cat and exhaust to get a little more power back or even increase because I am assuming that the car has at least 97,000 miles (odometer does not work and pondering to send it to Palo Alto service and paid 300).


As always, thank you in advance for all your valuable input.

J.P.

Just came back after installing the new tires: the car does not vibrate anymore, so I will assume shocks are fine. also old tires were really dry rotten, hard and squared indeed, so this solves part of the puzzle, but car still bucks on first.
 

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rad cap mark under hood is sure sign of engine mounts, methinks.
Get some alum. foil from the kitchen, and form a small 'loose' ball with it, then sit it on top of rad cap and gently close hood....unlatch and open hood....

by how much has the foil ball been compressed?

Keep the O² sensor - just get an exhaust shop to make a bung for the O² sensor on new exhaust.
 

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Discussion Starter #4
I just took a good look at the situation: The radiator cap imprint on the inner side of the hood was due to the radiator neck to be slightly elevated and out of position and the lack of rubber grommets for said radiator, so it does not appear to be connected to the bucking issue, even when a swaying engine could cause a tugging on the hose and pushing radiator up, but I replace grommets and bent radiator neck and it does not move or hit anymore.
I also checked the throttle mechanism and linkage and there are no obstructions or seizing.
With hood open and revving engine I noticed engine tilts slightly to the right, but not hesitation and engine revs smooth all the way. What is really funny is that this only happens in first gear and after that you can rev the engine to the limit and engine runs fine and car feels fine.
 

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Still likely to be worn/soft engine and trans mounts. You won't see much torque reaction (movement) by revving the engine in neutral. You'll get the most torque reaction starting the car moving in 1st gear.

Check how close the fan is to the body work at the bottom. The fan should be centered in the shroud. If the fan is close to hitting the body and isn't centered in the shroud, the motor mounts are probably overdue for replacement.
 

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The bucking in first might be ignition, does it have reasonably new plugs? What is bucking for you, like a miss or maybe a hesitation? Or is it running fine and just maybe something like really crazy clutch chatter?

Cheers,
 

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Discussion Starter #7 (Edited)
I keep checking about the bucking issues and it seems is a combination of two things: Clutch seems to vibrate when you release it and I feel a little more slippage and some noises when clutch is depressed, so now I'm sure clutch will have to be replaced, also, if you do not release the clutch too fast it aleviates bucking issue.
I been hearing it is a pain in the neck to do a clutch job without removing the engine and transmission together, but I've seen some postings saying it is perfectly doable.
I do not have a car lifter so I will work under the car with jack stands, as always, and I should think this can be done, but I'd like to hear more opinions on the matter (I also have an engine hoist, so getting the whole engine could also be an option, but I think this is too much for a clutch job, so please let me know your two cents if you can.
The other think about the bucking seems to be related to fuel starvation with wide open throttle and this is not only happening in first gear but now when the gas pedal is fully depressed, so I thought it could be partially clogged injectors, throttle position sensor, VVT or something else. Problem is getting worse, and I tried with a full tank of gas just to see if this was an issue with the submerged fuel pump, but no difference.
Fuel pumps and filters are new, and fuel injectors were serviced, but after I installed them they clogged up due to corrosion, because they where cleaned with water base detergents instead of petroleum based solvents and (now I know) you need to installed them and keep the fuel going, but I instead ran engine only once and then I did the head job, so they all clogged up due to atmospheric moisture, and car would not run until they were cleaned again, but I'm suspecting they are not up to par, so I might hve to replace them, but I also wanted to know if there is some testing to make sure injectors are at fault or something else.

Thanks again.

J.P.
 

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Discussion Starter #8 (Edited)
I'll check mounts again but now, with what appears to be a fuel starvation issue, I see more testing will be required. In any case I suppose mounts are the factory ones, so if engine has at least 97,000 miles (odometer does not work) and 33 years of age one needs to assume car will need motor mounts, but I'll check distance from fan to body work.

Thanks
 

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Discussion Starter #9 (Edited)
The bucking in first might be ignition, does it have reasonably new plugs? What is bucking for you, like a miss or maybe a hesitation? Or is it running fine and just maybe something like really crazy clutch chatter?

Cheers,
I guess the best way to explain this bucking issue is that it is very similar to when you try to start the car when in gear, so the car jerks back and forth until you depress clutch pedal and or release the gas pedal.
A few years back I had a similar issue with a small Fiat 124, and I had to pump the gas pedal several times so my car would not die on me and I was thinking it was a fuel issue related to a bad pump and a carburetor, but in the end it was just the distributor rotor.
I mentioned this before realizing you posted this, so here it goes: Spark plugs and wires are new (NGK's) and there is definitively a clutch chatter that is getting worse, so yes, clutch is kaput or close to it as I have the sensation pressure plate is not holding evenly and also felt a slight slippage. Moreover, if I don't release the clutch entirely, bucking is greatly reduced, but also improves if you go easy on the gas pedal. Now that I've been driving WOT on the highway one can feel car is either loosing spark or fuel, so instead of sputtering or hesitation the car feels like dying and looses RPM's. but if you ease on the gas the car recovers. You can also hear the engine revving smoothly until a certaing point and still bucks at low speeds, particularly in first gear, or fades out until you ease on the gas pedal, but engine does not stall, but feels that it would if you keep depressing the gas pedal.
I was pondering this could be de to the submersible in tank pump, so I filled the gas tank full, no difference and both pumps are new, same as fuel filter.

Thanks.
 

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your clutch sounds bad, as you say.

But, I'd also check the big air hose over the engine. If it has a small split, and you take off in 1st, that's when the engine torques over the most to the right....that can open a "small split", cause false air, and you will have a bucking bronco:)
You need to remove that hose, and check carefully for splits, where it is clamped to afm and plenum and the underneath too
 
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Discussion Starter #11 (Edited)
your clutch sounds bad, as you say.

But, I'd also check the big air hose over the engine. If it has a small split, and you take off in 1st, that's when the engine torques over the most to the right....that can open a "small split", cause false air, and you will have a bucking bronco:)
You need to remove that hose, and check carefully for splits, where it is clamped to afm and plenum and the underneath too
OK, as I was checking the A/C and I found I big compressor (front seal) leak, so I will have to replace it (Samden 507 I think), same as starter that has a driver that is dragging stuck, plus rear main seals, maybe front seals as well, water pump while I'm at it, clutch that is jittering and slipping and differential yoke/pinion seal, maybe guibo and shaft bearing and carrier. Probable input and output tranny shaft seals and intake manifold big round seals (hair thick cracks), so I guess I'll have to pull out engine or tranny or both of them, but I don't know what makes more sense (I am forgetting about motor and tranny rear mount), so what you guys think would make more sense? I could get compressor just by removing radiator and then do front seals and water pump. Remove intake manifold pipes and replace big seals and engine mounts and then concentrate on pulling transmission out (how do you deal with the shift stick?) or remove the whole thing?
After this is done I will focus on the air hose possible leaks you mention and see if I will finally be free as a bird, or not, since I need to repaint wheels and do the soft top.
Well the satisfaction that comes out when you get the car jobs done is really something and the wind in your hair is great!
 

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If you are going to change the a/c compressor. Pull the engine. Its much easier with it out.

You can change everything else on your list with the engine out except for the trans mount. Which is easy with the trans in the car.
 

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Discussion Starter #13
If you are going to change the a/c compressor. Pull the engine. Its much easier with it out.

You can change everything else on your list with the engine out except for the trans mount. Which is easy with the trans in the car.
Duly noted! So it'll be easier with tranny in the car? I was thinking the opposite with the exhaust in the way, but it'll be done for sure.

When I saw the Wheeler Dealers show about the Quadrifoglio they removed radiator, fan and then the compressor, but even when in my humble this is one of the best shows, they still cheat a little bit (or a lot) or take unexplained corners, but still I need to replace the manifold big seals and starter, so the engine will be out and see if (big seals) that cures part of the problem (and clutch). Last time I drove it it was not lossing power at WOT but still was bucking in first, so I guess is a combined issue, but I am having fun find it out the issues.

Thanks.:smile2:
 
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