Alfa Romeo Forums banner

1 - 20 of 33 Posts

·
Premium Member
Joined
·
622 Posts
Discussion Starter · #1 · (Edited)
This car was having a CE light at idle (1223 code), a rough idle, & it stalls when I let off the throttle when coming to a stop. It will start right back up, but I have to feather the throttle in order to get it to hold an idle. The stalling occurs regardless of temperature.

Servicing the injectors & replacing the dog bone engine mount got rid of the rough idle. Replacing the AFM got rid of the CE light at idle. A review of the service records indicated that the AFM had been tampered with in the past.

I'm now stuck with it stalling when I let off the throttle. If I wait until the car gets down to around 1500 RPM's before disengaging the clutch, it won't stall. However, if I let off the throttle & disengage the clutch at normal engine speeds, it will stall immediately. There is no sputtering or anything like that; it just dies as if the ignition switch was shut off. It will start right up again, but sometimes, I have to open the throttle a little on re-starting.

I put a smoke machine to it, & I saw that the idle controller & the EGR valve both leaked; not the gaskets or hoses, but the devices themselves. After replacing both pieces, the stalling problem persisted. I put the smoke machine on it again, & the new EGR valve leaks vacuum in the same manner as the original. This is now the only vacuum leak on the car. On the EGR valve, there are openings in the under-side of the diaphram housing such that you can see the shaft that ties the diaphram to the valve itself. This is where the smoke comes out when the smoke machine is put to the car. In fact, the new EGR valve does it worse than the original.

Is the EGR valve designed this way intentionally, or did I get a defective EGR valve?

All the usual suspects have been addressed on this car in recent years. I just did a t-belt; cam timing set with dies & TDC gauge; belt tensioned in accordance with last TSB on the subject. All fluids & filters new, plugs, coils, & modules replaced two years ago, & O2 sensor replaced in recent years. After resolving the 1223 code with a replacement AFM, there are no codes present. The stalling occured with both AFM's.

Otherwise, the car runs great in all respects.

Thanks in advance for any input.
 

·
Moderator
1991 164L
Joined
·
27,633 Posts
Sounds like ruptured EGR vac chamber diaphragm. Why don't you slip a thin metal shim between valve and intake boss to see if that gets rid of false air leak?

Steve
 

·
Premium Member
Joined
·
622 Posts
Discussion Starter · #3 ·
That's a good idea. I'll try that. However, the diaphram itself is fine. The leak is coming from below the diaphram; where the diaphram houising attaches to the valve.

That said, if a block-off plate makes the stalling go away, then I can safely conclude that I have a defective new EGR valve. Of course, that maybe of little comfort since sourcing another one is not exactly a slam-dunk proposition.:rolleyes:
 

·
Moderator
1991 164L
Joined
·
27,633 Posts
That's a good idea. I'll try that. However, the diaphram itself is fine. The leak is coming from below the diaphram; where the diaphram houising attaches to the valve.

That said, if a block-off plate makes the stalling go away, then I can safely conclude that I have a defective new EGR valve. Of course, that maybe of little comfort since sourcing another one is not exactly a slam-dunk proposition.:rolleyes:
Report your findings.
 

·
Premium Member
Joined
·
622 Posts
Discussion Starter · #5 ·
Archive problem

Will do. BTW, there seems to be a problem with the archives; at least on my end. Before I posted this, I searched the archives for EGR & got no results. Just for grins, I repeated the search after I posted this, & I still got no results.

Anyone else reading this, I'd appreciate it if you'd search the archives for EGR, & let me know if you come up with anything.
 

·
Premium Member
Joined
·
9,873 Posts
This car was having a CE light at idle (1223 code), a rough idle, & it stalls when I let off the throttle when coming to a stop. It will start right back up, but I have to feather the throttle in order to get it to hold an idle. The stalling occurs regardless of temperature.

Servicing the injectors & replacing the dog bone engine mount got rid of the rough idle. Replacing the AFM got rid of the CE light at idle. A review of the service records indicated that the AFM had been tampered with in the past.

I'm now stuck with it stalling when I let off the throttle. If I wait until the car gets down to around 1500 RPM's before disengaging the clutch, it won't stall. However, if I let off the throttle & disengage the clutch at normal engine speeds, it will stall immediately. There is no sputtering or anything like that; it just dies as if the ignition switch was shut off. It will start right up again, but sometimes, I have to open the throttle a little on re-starting.

I put a smoke machine to it, & I saw that the idle controller & the EGR valve both leaked; not the gaskets or hoses, but the devices themselves. After replacing both pieces, the stalling problem persisted. I put the smoke machine on it again, & the new EGR valve leaks vacuum in the same manner as the original. This is now the only vacuum leak on the car. On the EGR valve, there are openings in the under-side of the diaphram housing such that you can see the shaft that ties the diaphram to the valve itself. This is where the smoke comes out when the smoke machine is put to the car. In fact, the new EGR valve does it worse than the original.

Is the EGR valve designed this way intentionally, or did I get a defective EGR valve?

All the usual suspects have been addressed on this car in recent years. I just did a t-belt; cam timing set with dies & TDC gauge; belt tensioned in accordance with last TSB on the subject. All fluids & filters new, plugs, coils, & modules replaced two years ago, & O2 sensor replaced in recent years. After resolving the 1223 code with a replacement AFM, there are no codes present. The stalling occured with both AFM's.

Otherwise, the car runs great in all respects.

Thanks in advance for any input.
Oh, this sounds familiar! I have an EGR if needed mike.

J
 

·
Premium Member
Joined
·
622 Posts
Discussion Starter · #7 ·
Blocking off EGR made no difference. I'm still not thrilled at the fact that the brand new EGR valve leaks vacuum, but it may be that it's designed that way. I'd be interested to hear if anyone else has put a smoke machine to a 95.

What did make a difference was turning off the A/C. I think I might have a marginal alternator; so I checked it with my volt meter. With the A/C on, voltage is at 12.4 to 12.6. With the A/C off, voltage gets a little above 13, & the car no longer stalls on decel. In either scenario, the voltage comes up when I rev the motor.

I did notice during emissions testing that the machine read an idle speed of about 585 RPM (A/C was on), which I thought was a little low. So, either I have a low idle speed caused by something else, which prevents the alternator from charging at idle, or I have a marginal alternator.

With the A/C on at idle speed, the dash gauge reads just shy of the 1st mark past 12, & the charging system warning light is not on.
 

·
Premium Member
Joined
·
6,389 Posts
battery or alternator

check your battery for electrolyte level, and general robustness. Alternator brushes can be changed without removal of the alternator-- there is a thread somewhere on this procedure- about an hour job pretty easy.

I have never smoke machined any car. Have smoke checked a lot of electrical components tho. Sounds intriguing.
 

·
Moderator
1991 164L
Joined
·
27,633 Posts
If you block off EGR from intake do you still get smoke from it?
 

·
Premium Member
Joined
·
32 Posts
EGR search problems

Hi,

My 95LS just failed California smog testing because of high NOS and I suspect the EGR valve. Yesterday I searched on "egr" several times and also got no results . . .

Tim Carrico
 

·
Registered
Joined
·
4,067 Posts
The problem with searching "egr" is the forum will not allow you to search for a word with only 3 characters.
Charles
 

·
Premium Member
Joined
·
622 Posts
Discussion Starter · #12 ·
Using "egr valve" as a search term got me some results.

I opted to have the alternator completely rebuilt since the service records showed it to be original to the car. The battery is an Optima that's less than 2 years old & lives on a tender when not in use.

I did not do a smoke test with the EGR blocked off, but that's a good idea. I'll try it.

If the alternator doesn't fix the problem, then I need to verify that my EGR valve is not open at idle. It's brand new, but if the EGR valve solenoid failed, then that would be a problem (i.e. there'd be vacuum to the EGR valve at idle). Failing that, I'll probably have to go back in, & re-check cam timing, although I followed procedure to the letter.

TimCarrico, high NOS associated with the EGR system would result from a non-functioning EGR valve or EGR valve solenoid. With the car at idle, put a hand-held vacuum pump to the EGR valve's diaphram. When you pump it up, it should hold vacuum, & opening it with the vacuum pump should cause the motor to stumble and/or stall. If it doesn't hold vacuum, that means a ruptured diaphram. If it holds vacuum but doesn't impact the car's running condition, then it, and/or the passage in the intake plenum, is clogged. I'm not sure off-hand how to test the EGR solenoid. Bear in mind that there are a lot of other things that could cause high NOS.
 

·
Premium Member
Joined
·
622 Posts
Discussion Starter · #13 ·
The electric shop found that the alternator needed a voltage regulator & bearings. Some new OEM parts later, alternator reinstalled, & the problem still persists.

The good news is that I think I've found the culprit. The timing/rpm sensor appears to be faulty, but not in a way I've experienced before. Both signal wires (pins 1 & 2) have slight continuity to the shield wire (pin 3), & the shield wire has slight continuity to ground. Accordingly, the signal wires also have slight continuity to ground. We're talking 17 mega-ohms of resistance, but on any other sensor such as this that I've tested, it's always been an open circuit between the sheild & signal wires & ground. I've never seen one of these sensors do this before, but I'm pretty sure it's not right. It does have about 520 ohm of resistance between the two signal wires, & its output is around 2.0 volts A/C.

Just to be sure, I tested the sensor on a Motronic Spider that I have in at the moment, & it was a completely open circuit between the signal wires & the shield wire. It was also open between the shield wire & ground.

I'll order a new sensor & report back.
 

·
Premium Member
Joined
·
622 Posts
Discussion Starter · #14 ·
How about the thorttle position sensor?

Finding fault with the crank position sensor has gotten me looking at all the other sensors on the car, especially since I have no fault codes despite the fact that there is clearly a fault with the crank position sensor.

The only thing I found to be a bit off is the throttle position sensor. It has all the correct resistance values according to this web site: http://apps.bosch.com.au/motorsport/downloads/sensors_throttleposition.pdf It reads 5 volts between pins 1 & 2 with the key on, & the voltage reading does sweep progressively between pins 2 & 3 when the throttle is moved.

However, the manual states that the sweep should be from 0 volts at closed throttle to 5 volts at WOT. On this car, the voltage reading between pins 2 & 3 sits at 0.5 volts with the throttle closed. Is this cause for concern and/or replacement of the TPS? Has anyone else tested their 24V TPS in this manner?
 

·
Premium Member
Joined
·
6,389 Posts
havent checked that way

but the data sheet seems to show that the 'wiper protective resistor' value at zero degrees has range from 710-1300 ish ohms -- between terminals 2 and 3 -- which means there is a measurable voltage drop there. .5 volts at lets say 1000 ohms would be, .5 milliamps ; seems reasonable.

Funny enough, just last night I had this TPS off my auto car as I do about every 6 months. The wiper contact in mine seems to get dirty and wont go to full shutoff, leaving me with a high idle. Removing the TPS and spraying non residue contact cleaner in it always seems to make it correct. I would like to source a new TPS tho-- who has these?
 

·
Moderator
1991 164L
Joined
·
27,633 Posts
164 24v TPS 9946862
 

·
Premium Member
Joined
·
6,389 Posts
where can I buy it steve?

on the cheap-o? Cant seem to find it online!
 

·
Moderator
1991 164L
Joined
·
27,633 Posts
Alfa 164 24v TPS 9946862 sub numbers

on the cheap-o? Cant seem to find it online!
Beats me, maybe Rock Auto do a search if you have Bosch number.

http://airtexenginemanagement.com/pdf/pin_outs/5S5315.pdf

Report your findings.

Alfa: 60811198. Citroen: 1628 L1
Fiat: 9946862. Hyundai: 35170-23000.
Kia: 0K247-18-911. GM: 90323839.
Saab: 8857195. Toyota: 89452-050010
Volvo: 1336385-8

ALFA FOMEO 9946862,60549359,60811198,7637025
CITROEN 1628 1E,1628 L1,1920Z4,96038938
FIAT 60808043,7377025,9603893880
FIAT 9617220680,9625299980,
9946862,9947132
GM 90 323 839
HOLDEN 90323839
HYUNDAI 35170-22001,35170-22010,35170-23000
KIA OK011-18-911,OK247-18-911,OK30A 18911
OPEL 8 26 924
PEUGEOT 1628 1E
RENAULT 7701034407,7701047921
SAAB 4661062,8857195
TOYOTA 89452-0501
VOLVO 1336585-8
 

·
Premium Member
Joined
·
6,389 Posts
mike can you list one or two?

when i google it i get lots of pages of 'alibaba' "BUY TPS SENSOR IN BULK' etc! I only need one not 10,000!

thanks, bob
 
1 - 20 of 33 Posts
Top