concern about decreasing mileage, leaking FPR hose (long)
07-25-2003, 10:23 AM
#1
New Member
Thread Starter
Join Date: Sep 2002
Posts: 334
Likes: 0
Received 0 Likes
on
0 Posts
concern about decreasing mileage, leaking FPR hose (long)
First off, I apologize for all these questions I've asked this week after installing my gauge pak, but it was the first work I ever did on my engine (on any engine!), so I am of course a little nervous about my abilities to get it right.
Last Saturday I installed a VDO boost gauge and oil temp gauge. The temp gauge uses the oil pan plug sender and reads 210-230 F when hot.The boost gauge is tapped into the vacuum line that runs from the manifold to the FPR. The Tee used to tap into the line was a little too big, and so only about a 1 cm of the tee is inserted into the hose on each end. Boost is reading ~12 psi (180 hp engine, no chip), so it is on target. Maximum vacuum reading when releasing the accelerator is about -25 mmHg.
My concern: I've noticed my mileage has dropped this week. I used to run right about 21.9 mpg. This week I'm running at ~19 mpg. I've heard the jokes that the mileage will drop because I will be constantly playing with my boost gauge, but I've reset the calculator several times and not driven agressively. Funny thing is, I lost 0.4 mpg in my mileage while the car sat in the garage overnight last night (dropped from 19.0 to 18.6).
One more thing. Two days before installing the new gauges, I hopped in my car after work, where the car had sat in 115 F sunshine all day (Phoenix summer, baby!). Upon starting the car, fuel gauge needle went to the very last tick mark before "E", and my trip computer said I had 5 miles of gas left. This blew me away, because I had more than a quarter tank of gas the day before. As I drove away from work, the needle moved to "E" and the trip comp read 0 miles of gas remaining. Sweating nervously, I drove as economically as possible. However, after 5 miles of driving, my gauge had returned to the 1/4 mark and the trip comp said I had 65 miles left.
So now I'm confused about what the problem is, and I want to be sure I'm not risking engine damage if there is something wrong with the FPR line. If my FPR line was leaking, the car would run lean. Would I not have better mileage then? Would I have the CEL on because I was running too lean? And wouldn't my engine temp run hotter?
Or is this just another case of a faulty TT instrument cluster?
What would be the best way of know if my FPR was malfunctioning?
Any help and advice would be greatly appreciated (and learned from!).
Last Saturday I installed a VDO boost gauge and oil temp gauge. The temp gauge uses the oil pan plug sender and reads 210-230 F when hot.The boost gauge is tapped into the vacuum line that runs from the manifold to the FPR. The Tee used to tap into the line was a little too big, and so only about a 1 cm of the tee is inserted into the hose on each end. Boost is reading ~12 psi (180 hp engine, no chip), so it is on target. Maximum vacuum reading when releasing the accelerator is about -25 mmHg.
My concern: I've noticed my mileage has dropped this week. I used to run right about 21.9 mpg. This week I'm running at ~19 mpg. I've heard the jokes that the mileage will drop because I will be constantly playing with my boost gauge, but I've reset the calculator several times and not driven agressively. Funny thing is, I lost 0.4 mpg in my mileage while the car sat in the garage overnight last night (dropped from 19.0 to 18.6).
One more thing. Two days before installing the new gauges, I hopped in my car after work, where the car had sat in 115 F sunshine all day (Phoenix summer, baby!). Upon starting the car, fuel gauge needle went to the very last tick mark before "E", and my trip computer said I had 5 miles of gas left. This blew me away, because I had more than a quarter tank of gas the day before. As I drove away from work, the needle moved to "E" and the trip comp read 0 miles of gas remaining. Sweating nervously, I drove as economically as possible. However, after 5 miles of driving, my gauge had returned to the 1/4 mark and the trip comp said I had 65 miles left.
So now I'm confused about what the problem is, and I want to be sure I'm not risking engine damage if there is something wrong with the FPR line. If my FPR line was leaking, the car would run lean. Would I not have better mileage then? Would I have the CEL on because I was running too lean? And wouldn't my engine temp run hotter?
Or is this just another case of a faulty TT instrument cluster?
What would be the best way of know if my FPR was malfunctioning?
Any help and advice would be greatly appreciated (and learned from!).
07-25-2003, 11:18 AM
#3
Totally agree with John... the gauges and your work are not...
IMO, related.
Your instrument cluster is going bad and feeding the MPG info incorrectly into the display. The needle is a leading indicator of such a failure. This is a delaer only fix and one that (unless you are still in warranty) will cost about $650 to fix.
Many of us have had our IC go bad... Sorry. Watch those needles and KNOW how much fuel you have or it might be a long walk in 115 degree heat.
Your instrument cluster is going bad and feeding the MPG info incorrectly into the display. The needle is a leading indicator of such a failure. This is a delaer only fix and one that (unless you are still in warranty) will cost about $650 to fix.
Many of us have had our IC go bad... Sorry. Watch those needles and KNOW how much fuel you have or it might be a long walk in 115 degree heat.
07-25-2003, 01:37 PM
#4
Could be the cluster and/or fuel sending unit. Had both of mine replaced and works fine now>>
I still wouldn't trust the fuel gauge before filling up at the pump. I never run it below 1/4 of a tank. All this should be covered under warranty providing your mileage isn't over 50k. -Doug
Thread
Thread Starter
Forum
Replies
Last Post
kenny (dremel)
A4 (B5 Platform) Discussion
7
08-22-2003 05:53 AM
CP
A4 (B5 Platform) Discussion
0
01-29-2000 05:34 PM
