If I disconnect the vac. line to the EGR and pull a vacuum on it, the engine stumbles at idle.
01-13-2007, 01:58 PM
#1
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If I disconnect the vac. line to the EGR and pull a vacuum on it, the engine stumbles at idle.
This suggests to me that the EGR passage is not plugged up. Agreed?
I am getting the EGR insufficient flow and temperature too low codes. Aside from the passage clog issue, is it plausible that either the temperature sender is bad, or the vacuum solenoid is bad? Any BTDT?
(State inspection is next month
I am getting the EGR insufficient flow and temperature too low codes. Aside from the passage clog issue, is it plausible that either the temperature sender is bad, or the vacuum solenoid is bad? Any BTDT?
(State inspection is next month
01-13-2007, 02:43 PM
#2
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Re: If I disconnect the vac. line to the EGR and pull a vacuum on it, the engine stumbles at idle.
I had the code for insufficient flow at one point too--did the vacuum test and had similar result to yours. . . ended up replacing some vacuum lines and it solved the prob!
I bought a new EGR valve (still unopened) from autohausaz that I procrastinated on returning that I'd be pleased to sell to someone at a decent savings by the way . . .
Cheers,
Chris
I bought a new EGR valve (still unopened) from autohausaz that I procrastinated on returning that I'd be pleased to sell to someone at a decent savings by the way . . .
Cheers,
Chris
01-14-2007, 06:05 PM
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Just went thru the same diagnosis - was the EGR solenoid
Just went thru the same diagnosis.
1. Vacuum on EGR valve makes engine stumble (EGR valve OK).
2. Measure with Vag-Com Group 17 Block 4 (EGR temp) rises above 65C when vac applied to EGR valve (EGR temp sensor OK).
3. Activate solenoid with Vag-Com (output tests), makes the solenoid click audibly. (electrical connections OK).
4. With engine running check if vacuum present at EGR solenoid (vac line that goes to check valve and vacuum reservoir).
New EGR solenoid P/N 054906267A (note updated "A" P/N) is around $132. Found a used EGR solenoid (P/N 054906267) from a '93 Audi 90 at a salvage yard for $10 which luckily worked fine. Same EGR solenoid was used in most Audis 1990 thru 1998.
On my '96 A6Q it takes about 15 mins to change out. Just two phillips screws and bunch of vacuum lines. Draw a diagram first so you don't get them mixed up. No need to remove the air cleaner/MAF. Also is a good time to replace any crumbling vacuum lines.
Do a search (code #16785 or "Insufficient EGR flow") and there is an excellent write-up with pix...
1. Vacuum on EGR valve makes engine stumble (EGR valve OK).
2. Measure with Vag-Com Group 17 Block 4 (EGR temp) rises above 65C when vac applied to EGR valve (EGR temp sensor OK).
3. Activate solenoid with Vag-Com (output tests), makes the solenoid click audibly. (electrical connections OK).
4. With engine running check if vacuum present at EGR solenoid (vac line that goes to check valve and vacuum reservoir).
New EGR solenoid P/N 054906267A (note updated "A" P/N) is around $132. Found a used EGR solenoid (P/N 054906267) from a '93 Audi 90 at a salvage yard for $10 which luckily worked fine. Same EGR solenoid was used in most Audis 1990 thru 1998.
On my '96 A6Q it takes about 15 mins to change out. Just two phillips screws and bunch of vacuum lines. Draw a diagram first so you don't get them mixed up. No need to remove the air cleaner/MAF. Also is a good time to replace any crumbling vacuum lines.
Do a search (code #16785 or "Insufficient EGR flow") and there is an excellent write-up with pix...
01-14-2007, 07:52 PM
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Re: Just went thru the same diagnosis - was the EGR solenoid
Ya know, now that you point that out, reminds me that in my case I did have to replace the solenoid too (as well as vacuum lines noted separately).
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