VTEC not engaging, speedo wildly inaccurate
09-21-2015, 08:04 AM
#1
Registered User
Thread Starter
Join Date: Dec 2011
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
VTEC not engaging, speedo wildly inaccurate
Ok, first things first. I DID use the search bar, I haven't found anything that seems to fit my specific circumstances.
Recently did an engine swap into my 02 AP1. Used motor with known good compression, 240 across all four cylinders, 26k on the engine/trans.
Swap goes fine, engine runs great for about a week. The only issue was a CEL for secondary air pump flow, which ended up being a bad vacuum line.
All of a sudden, 1000 miles later, the car will not engage in VTEC. It will go right up the 6.5K rpms, and then its like I hit the governor. A CEL pops on for a tick of a second and goes out immediately. It does not come on at all after.
Today I noticed the speedo was highly inaccurate. GPS showed me going ~70, speedo indicated 40 something. The car still runs fine, up until the VTEC limit.
I understand that the VSS does play a factor in VTEC.
I'm not really sure where to start here, because the car was running so well for around 1k miles. Is it likely that the issue is a bad VSS wire/connection? shouldn't that throw a CEL for loss of VSS though?
I'm not sure where to trace this/start troubleshooting.
Recently did an engine swap into my 02 AP1. Used motor with known good compression, 240 across all four cylinders, 26k on the engine/trans.
Swap goes fine, engine runs great for about a week. The only issue was a CEL for secondary air pump flow, which ended up being a bad vacuum line.
All of a sudden, 1000 miles later, the car will not engage in VTEC. It will go right up the 6.5K rpms, and then its like I hit the governor. A CEL pops on for a tick of a second and goes out immediately. It does not come on at all after.
Today I noticed the speedo was highly inaccurate. GPS showed me going ~70, speedo indicated 40 something. The car still runs fine, up until the VTEC limit.
I understand that the VSS does play a factor in VTEC.
I'm not really sure where to start here, because the car was running so well for around 1k miles. Is it likely that the issue is a bad VSS wire/connection? shouldn't that throw a CEL for loss of VSS though?
I'm not sure where to trace this/start troubleshooting.
09-21-2015, 08:10 AM
#2
Registered User
Thread Starter
Join Date: Dec 2011
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
A few other things of note:
The only mod on the car at all is a full length 5zigen header (came on the new engine).
I did have an issue a 4-5 days ago where it was low on coolant (suspected air bubble in the system when refilling with coolant after engine swap). The dummy gauge got high for 1-2 minutes in stop and go traffic, but it never overheated or anything. I added coolant to it, and it was fine after that. Vtec worked without issue afterward until yesterday
The only mod on the car at all is a full length 5zigen header (came on the new engine).
I did have an issue a 4-5 days ago where it was low on coolant (suspected air bubble in the system when refilling with coolant after engine swap). The dummy gauge got high for 1-2 minutes in stop and go traffic, but it never overheated or anything. I added coolant to it, and it was fine after that. Vtec worked without issue afterward until yesterday
09-21-2015, 08:57 AM
#4
Registered User
Thread Starter
Join Date: Dec 2011
Posts: 24
Likes: 0
Received 0 Likes
on
0 Posts
I almost started to message you direct, haha. Your knowledge about the secondary air punp flow was spot on.
Took the car out for lunch today, speedo still..."off" but VTEC suddenly working again. I am assuming this makes the ground even more likely the culprit?
Any chance you have a pic as a reference?
09-21-2015, 09:06 AM
#5
09-21-2015, 09:23 AM
#7
Other way around. 70MPH = 112KPH. His 70MPH (GPS) shows 40.
Trending Topics
09-21-2015, 09:48 AM
#8
Moderator
windhund116 shows proper ground pic. make sure it is on the cylinder head, and not run to the body instead.
It is the direct ground for the VSS, among other things.
It is the direct ground for the VSS, among other things.