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Discussion Starter #1
Newbie here, just beginning to have fun. My 164 will accelerate smoothly if a light touch is used on the throttle, but at medium to hard acceleration it will buck and almost die for a split second and then comes back on with lots of power for a second or two and then nearly dies again.

Ran fine for a week or so and then this started. Idle sometimes varies up and down between 600 and 1000 rpm. Right now its steady around 800.

I can't trust it to be my daily driver until I get this straightened out. Any ideas?

Capm Woody
St. Pete Beach
 

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What you described are typical symptoms of an air leak - most likely there is a split at the big black rubber hose between the air filter box and the throttle!
 

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I had a similar problem very recently and it turned out to be a bad high tension lead from the coil to the distributor. It was a very "shocking" discovery to say the least.:eek:
http://www.alfabb.com/bb/forums/164-168-1991-1995/49528-acceleration-hesitation.html

OTOH, I had a leaky intake boot some years back and it was very similar - except it was more pronounced when going around left hand corners (engine would shift ever so slightly away from air filter housing, stretching and opening the crack in the boot piece - I think)

Both are easy to check - for the intake boot just start up the engine and manhandle the rubber piece between the MAF and the TB. (note any changes in RPM - or you may actually find the crack with your hands)
For the bad ignition I do NOT recommend manhandling high voltage wires! Instead, at night or in a dark garage get a spray bottle with some water and spray the wires lightly and if you have a bad connection you will see arcing.
 

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You didn't say whether your 164 was a 91-93 12v model or the 94-95 24v. These symptoms can be caused by different problems depending on which series your car is.
 

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You didn't say whether your 164 was a 91-93 12v model or the 94-95 24v. These symptoms can be caused by different problems depending on which series your car is.
Whichever the model troubleshoot for air leak/crack in tube with engine idling by grapping air flow meter and try to move it up and down to see if idle changes. If so tube probably cracked but also be sure air cleaner box 4 rubber mounts are not broken. Broken mounts can cause inlet hose to crack, too.
 

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Steve, of course, is correct; however, with 24v engines, bad/dirty connections at the ignition modules can cause similar symptoms.

Also, whenever you ask a question concerning your 164, it really helps to identify which model you are talking about.
 

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Discussion Starter #7
Thanks for all the advice

I'll have some very specific things to look for this weekend. I had a Fiat Brava with FI for a short while, but all my other cars had carbed engines. FI is still new to me. Sorry for not mentioning mine is a 1992 S model.
 

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I'll have some very specific things to look for this weekend. I had a Fiat Brava with FI for a short while, but all my other cars had carbed engines. FI is still new to me. Sorry for not mentioning mine is a 1992 S model.
Man, I had a bunch of Fiat Bravas most were fuel injected but had one 78Super Brava (first year of Brava body with 131 1800 carbed engine) and also had 79 smogged to death carb 2L version. But all my 80 1/2 through 82 models had Bosch injection. Loved those models.

As for your 164 problem if it is inlet corragated tube for air flow meter be advised S model tube larger the B/L models and longer than LS/Q models so you will need S specific and after a long dry spell of none available I understand they are now again available. There was an adapter being sold by Di Fatta Brothers - Alfa Romeo and Fiat Parts Sales and Service to go with LS/Q tube to make it long enough. I made one with a clothes dryer vent kit from Home Depot and LS/Q tube and good end from a S tube.

You can temp repair them with Shoe Goo (auto goo) in a tube and some folks even have used an old rubber innner tube sleeve clamped over it for temp repair.


The S tube part number is or was 60547303
 

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Discussion Starter #9
Spent a few hours on it today and could find no obvious air leaks. However, all the hose tightening and pulling and tugging made it run better. Still not up to driveable status.

The AFM is kind of dirty. Flap seems to work OK but how do you know for sure? How do you clean it? Also, is the plastic cover on it supposed to come off to inspect the contacts? I'd sure like to visit friends for Thanksgiving and the 164 is my only way to get there.

One more question. When I ordered parts from DiFatta Brothers, I ordered for a 1991 by mistake. Mine is a 92. Everything fit except the serpentine multi-groove belt. It's just a little bit too short and no amount of tugging will get in on. Might there be a slight difference between the 91 and 92? The old belt does not have as many grooves and I have to tighten it too much to stop the squeeling and I don't want to over stress the bearing in my new water pump.
 

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Spent a few hours on it today and could find no obvious air leaks. However, all the hose tightening and pulling and tugging made it run better. Still not up to driveable status.

The AFM is kind of dirty. Flap seems to work OK but how do you know for sure? How do you clean it? Also, is the plastic cover on it supposed to come off to inspect the contacts? I'd sure like to visit friends for Thanksgiving and the 164 is my only way to get there.

One more question. When I ordered parts from DiFatta Brothers, I ordered for a 1991 by mistake. Mine is a 92. Everything fit except the serpentine multi-groove belt. It's just a little bit too short and no amount of tugging will get in on. Might there be a slight difference between the 91 and 92? The old belt does not have as many grooves and I have to tighten it too much to stop the squeeling and I don't want to over stress the bearing in my new water pump.

Belts the same for 91-93 12v V6 engines. Did someone put the top mounting bolt for a/c compressor in backwards so end of bolt and nut in the way for full movement of idler pulley arm? Does arm have correct 164 pulley on it or maybe a slightly larger one from a Ford, etc? I know you probably can't answer that last question but these are possible reasons belt seems to short.

Does belt have an Alfa part niumber on it or aftermarket and what are numbers on it? As for width of belt if there are more than 7 grooves in it you are right it is wrong belt. It has to fit widtch of crank, water pulley and outer area of a/c pulleys.

Post picture(s) of idler pulley and belt if you can.

As for AFM cover was originally sealed on tight so probably somebody has tried to play with clock spring. Nothing to be said about that except you can check to see if copper wiper and circuit board grid clean. as for inside air inlet and flapper valve there is usually some oil film and maybe dirty so if you take it off car you can spray clean it with some carb cleaner if you like.

Pretty hard to second guess what maybe causing rough running idling but you can alos remove idle actuator and spray clean it inside inlet end with rubber grommet on it. If that rubber grommet fits loose in back of intake you can wrap it with electrical tape to get a good tight fit (another area to check for air leak).

Check small vac hose to fuel pressure regulator on fuel rail back end and cruise control L-elbow vac connection and follow that line to round vac bottle inside front fender (also for carbon cannister in there too.

Many places for vac leaks in fender area and to cruise actuator near air cleaner.
 

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Spent a few hours on it today and could find no obvious air leaks. However, all the hose tightening and pulling and tugging made it run better. Still not up to driveable status.

The AFM is kind of dirty. Flap seems to work OK but how do you know for sure? How do you clean it? Also, is the plastic cover on it supposed to come off to inspect the contacts? I'd sure like to visit friends for Thanksgiving and the 164 is my only way to get there.

One more question. When I ordered parts from DiFatta Brothers, I ordered for a 1991 by mistake. Mine is a 92. Everything fit except the serpentine multi-groove belt. It's just a little bit too short and no amount of tugging will get in on. Might there be a slight difference between the 91 and 92? The old belt does not have as many grooves and I have to tighten it too much to stop the squeeling and I don't want to over stress the bearing in my new water pump.
One thing to check is the seal on the Idle valve control on back of plenum, sometimes those seals can go bad and cause a little funky running.

Also check your distr/cap and rotor and all wires. I had same issue with a customers car last week and it ran smooth if taken up slowly but when you hit it hard it would stumble, sput and spew!
replaced those as well as 1 wire that seems to have a broken lead. Also adjusted Min/max sensor on throttle which was slightly off and that fixed the problem. Also there was a little slack in the throttle cable which I think was part of the problem when you hit it to full throttle. The car ran great after that. May not be your specific issue but something else to look at.

Also just another note. Make sure your AFM plug is tight, use some dielectric grease, as well as on the min/max switch. Also check your injector wire harnesses to see if they are snug and not missing the wire clips. That is another thing I find with these cars is loose injector harnesses that can cause stumble as well.
grease those too.

Might want to change the fuel filter while your messing around with things...

Hope that helps?
Jason
 

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Discussion Starter #12
No Luck Yet

I haven't posted a picture yet, so if it doesn't work, the pix can be seen at:

New Page 1

On the belt situation, I saw that the AC compressor bolt was in backwards so I pulled the belt. Then I found that even though the bolt is in backwards, the idler arm is still able to move within its full range, as can be seen by the clean areas where the tightening bolt is. I have centered the idler arm so you can see that it has full range of motion. The arm does not move far enough to touch the AC compressor bolt. Whether the idler is the right one or not, I can't say.

The belt that is too short is in an Alfa-Fiat-Lancia box from DiFatta Brothers.
To the right of the bar code is the number 60571636.
Under the bar code is the number *0060571636001*
This is also the number printed on the belt.
It has seven ridges and 6 grooves.
The one on the car now is obviously not correct.
It has five ridges and four grooves.

As for the main problem, I have not been able to find any leaks so far. I've replaced a few of the hoses and hose clamps that looked suspect, any of which could have been the problem, but no improvement since yesterday. It will only idle for a minute or so, then die. Also takes about two or three times as long to start as it used to. Always starts though. Still need to get to the canister in the fender tomorrow.

CapmWoody
St. Pete Beach
 

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That part number is for correct belt not sure why you can't get it on with backwards bolt end and nut out of the way.
 

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As for being hard to start and stay running and original problem of no power wide open throttle if no air leaks in inlet tube and if dizzy cap at rotor check out I would be checking fuel pump pressure and fuel flow rate.

I also always verify cam timing with engine crankshaft pulley at top dead center and do a compression check of each cylinder to be able to base line engine condition.
 

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As for being hard to start and stay running and original problem of no power wide open throttle if no air leaks in inlet tube and if dizzy cap at rotor check out I would be checking fuel pump pressure and fuel flow rate.

I also always verify cam timing with engine crankshaft pulley at top dead center and do a compression check of each cylinder to be able to base line engine condition.
My bet is cam timing as well if all other is OK.
I was just going to post that.

Jason
 

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Maybe not the fuel pump per se if the car starts every time. Might be a clogged fuel filter (i.e. is OK in low pressure situations, can't keep up on higher demands).
Don't forget the vacuum hose that goes to the crankcase ventilation system behind the rear cylinder head either.
 

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Low RPMs and stumbles when throttle is opened suddenly?
One possibility: Distributor cap or rotor or plugs/wires
I hear you saying, "Why?" At low RPMs, there is little flow to be restricted (cfm-wise) and so the cylinders get a full charge of air. The plugs don't want to spark in high pressure air (10:1 compression, remember, and at low RPM not much spark advance). So other things break down first if they're weak. Check the inside of the dist cap and the rotor. We had one car with a nasty crack fully across the dist cap, exposing _all_ of the rods connecting the various electrodes in ways you'd not want to have happen in public. Another car's rotor lost its nose piece. Another car's graphite nubbin connecting the coil input to the rotor center was worn away and really missing (as in not there at all). All of these cars actually ran this way, just not well. It was amazing.

Michael
 

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Discussion Starter #18
Back to the fun after thanksgiving. I did check the cam timing and it appears to be one tooth off on the back cam and possibly that much on the front cam. Hard to tell exactly because of the way the front cam is marked. I know it was right on when it was set. Is that enough to cause such bad running? I ran out of time today, but tomorrow I'll set the timing again. What causes the timing belt to jump time? I've never had a car do this before. Should the timing belt idler move any when the car is idling? I was careful not to over-tighten, as the instructions say. Perhaps it should have been tighter. I know I always honked down pretty good in my Fiat idlers.

CapmWoody
St. Pete Beach
 

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Now that Thanksgiving is over I can get back to the important stuff. I did check the cam timing and it appears to be one tooth off on the back cam and possibly that much on the front cam. Hard to tell exactly because of the way the front cam is marked. I know it was right on when it was set. Is that enough to cause such bad running? I ran out of time today, but tomorrow I'll set the timing again. What causes the timing belt to jump time? I've never had a car do this before. Should the timing belt idler move any when the car is idling? I was careful not to over-tighten, as the instructions say. Perhaps it should have been tighter. I know I always honked down pretty good in my Fiat idlers.

CapmWoody
St. Pete Beach
 
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