Hi Gang,
I have a LTX12s on a street ported 13BT that won't start. It cranks, but there is an intermittant 'chug' sound; very similar to the sound a distributor engine makes when you get two of the spark plug wires mixed up and on the wrong plugs.
I reviewed the wiring and have identified which coils are driven by the orange and yellow wires, then confirmed that they are going to the correct plugs. Viewing from the left side, L1 = Bottom Left, T1=Top Left L2=Bottom Right T2=Top Right.

What else could be wrong here?

THX!!

- kel -

 

You can hear it here:

http://www.ajaxoftherockies.com/rx7/start.wav

It's most obvious around 7 seconds

- kel -

 

Update: If I unplug the wire from the Trailing #2 plug, the 'chug' goes away.

 

is the ltx12s programmed for 13bt or 20bt?

how did you put the cas in ?

 

It is programmed for the 13BT. I bought this car last year and put several thousand miles on it. I live in an area with emissions tests, so when the tags came due I put it up on blocks to add a Bonez hi-flo cat and replace the air pump & associated equipment.
While apart, I re-plumbed the fuel per reted's dual feed design, had the secondary injectors rebuilt by RC Engineering and cleaned up misc stuff.
Before this work, the car ran okay, and intermittantly would run fantastically well - fastest car I've had. Other times it ran like a dog, would buck while cruising and blow flames under hard acceleration.

My plan after getting the emissions back on was to tune properly, get the intermittant trouble traced down and emissions test passed However, after the work (and sitting for several months due to weather) it won't start with the symptom described.

The short answer to question two is, I didn't install the CAS. That said, I did check the timing according to the Microtech manual and it looked correct.

(BTW, it's good to see you back on the forum)

- kel -

 

Anyone?

- kel -

 

Sounds like timing! Did you install the T2 CAS correct?

 

I thought it sounds like timing also, but it's intermittant. The CAS hasn't been off the engine since I bought the car. Atkins did the rebuild and I had been driving it up until a few months ago when I put it on the blocks to add wideband, cat and some other stuff.

I have some fuel issues as well that were contributing to the no-start problem. If I spray starting fluid into the intake while cranking, it tries to start but never does. The chug happens, but not every revolution like you'd expect. you can sort of hear that in the audio file. Anyway, If I disconnect the T2 coil, I can get it to start and idle while spraying the fluid.

kinda weird, and I'm unsure how to troubleshoot the issue. I suspect the primary injectors are at fault for the fuel problem and am going to replace them later today. After that I should be able to start it without the fluid and with T2 disconnected.

I appreciate your thoughts


- kel -

 

Do you have the laptop software and dongle? If I remember right on the data gauge screen theres a status list for sensors, might be worth looking to see if there is a timing error. This was the case for me and the culprit was interence in the cas signal probably from spark plug wires sitting next to it. Relocated the cas wire away from them, threw on some extra split loom and was in business.

Worth checking anyways, its a cheap fix haha

 

that's a good idea. I have the dongle and software, but didn't see any errors while trying to get it to start.

Interference in the CAS wire makes real sense based on what's happening. Could also explain the intermittant crappy running I noted a couple of posts ago.

Thanks for the suggestion!

update will follow

- kel -

 

did you try putting a few drops on ATF in it? CAS def could be it if it isnt getting any spark. If its a fuel issue.. Do you hear your fuel pump prime when you turn the key?

 

Take the cas out and put it in correctly from scratch.

Check the wiring and make sure the triggers are going to the correct place.


Also show me your fuel and timing maps out of your microtech.

 

How does the plugs look ?

 

Sandrock: on advice from rx72c in other posts, I put MMO into it because it had been sitting so long. Did not help. Fuel is okay, I put in new plumbing per reted's dual-feed design and it has a walbro 225 supplying it. Although, I have reason to believe the primary injectors may be bad.

Rx72c: I will re-install the CAS today. Searching now for correct procedure. Also will confirm wiring from CAS to ECU. My map will follow later today

Oemfd: Plugs are new. I replaced them as first step in troubleshooting this new starting problem.

Thanks to all!


- kel -

 

Okay, here's what I've seen/done so far. I pulled the CAS, confirmed the correct wire colors and re-installed it following proper procedure.

Found the cable splice for the CAS had the shittiest solder job I've ever seen; I could solder better when I was 10 years old. Also, the shield was cut back so that there was a full 6 inches of exposed/unshielded wire from the CAS connector.

So, I cut the cable apart, soldered it properly and improvised a shield with aluminum foil around the exposed shield braid and wires, then covered the new shield with heat-shrink making a proper shielded cable up to the CAS.

Also, the exposed part of the CAS cable was draped across the spark plug wires for the front rotor. While things were apart, I repaired the wire guides for the plug wires and routed them correctly. Since there was enough slack, I routed the CAS cable over the top between the TMIC bracket and the solenoid valve bank thereby keeping it far away from the ignition wires

Tomorrow, I put it all together and try the start again.

Update later...


- kel -

 

It Runs!

Yes, I found enough stuff to fix that i can get it started now. After fixing the CAS cable, I started reading a ton of posts here on the Microtech forum. I discovered the test mode and what it does; that helped me identify that the P2 injector was bad.

So, I put it all back together and calibrated the TPS. Then, with a bit of coaxing, it started and idled badly. I reviewed several of the posts from rx72c and using his maps was able to get it to "idle" - fast, but fairly smooth and AFR around 12.9. I'd like to get the idle down from 1800rpm now and then get the rest of the map corrected.

Something still seems wrong in the ignition, too. It still 'chugs' while cranking just before it catches hold and starts. As before, If I unplug T2 coil, it doesn't make that sound. Here're two startups. I performed the timing setup per the manual after the engine warmed up.

http://www.ajaxoftherockies.com/rx7/start2.wav

To me, it sounds like the spark is happening way early on the "compression stroke" and kicking back against the starter. Anybody know if that is normal? I don't recall that sound when I was driving it daily.

Here's my map as it is now, with what it was before my research and map comparison:


Screen 1: Idle
---- --- Is now --- Was
30"hg --- 1.38 --- 2.05
25"hg --- 1.48 --- 2.10
20"hg --- 1.33 --- 2.24
15"hg --- 1.71 --- 2.24
10"hg --- 2.00 --- 2.71
05"hg --- 2.10 --- 3.81
00"hg --- 2.56 --- 4.19
2 psi --- 4.95 --- 4.95
4 psi --- 4.95 --- 4.95
6 psi --- 4.95 --- 4.95
8 psi --- 4.95 --- 4.95
10 psi --- 4.95 --- 4.95
14 psi --- 4.95 --- 4.95
16 psi --- 4.95 --- 4.95
18 psi --- 4.95 --- 4.95
20 psi --- 4.95 --- 4.95



Screen 8: Load Map
30"hg --- 1.76 ---
25"hg --- 1.52 ---
20"hg --- 0.86 ---
15"hg --- 1.81 ---
10"hg --- 3.00 ---
05"hg --- 3.90 ---
00"hg --- 4.81 ---
2 psi --- 5.62 ---
4 psi --- 6.10 ---
6 psi --- 7.14 ---
8 psi --- 7.86 ---
10 psi --- 8.48 ---
14 psi --- 8.67 ---
16 psi --- 9.00 ---
18 psi --- 9.48 ---
20 psi --- 10.00 ---


Screen 17: RPMwot OFF
500 --- 00 ---
1000 --- 00 ---
1500 --- 00 ---
2000 --- 00 ---
2500 --- 00 ---
3000 --- 00 ---
3500 --- 00 ---
4000 --- 00 ---
4500 --- 00 ---
5000 --- 00 ---
5500 --- 00 ---
6000 --- 00 ---
6500 --- 00 ---
7000 --- 00 ---
7500 --- 00 ---
8000 --- 00 ---
9000 --- 00 ---
--- ---

Screen 18: RPMcrs OFF
500 --- 00 ---
1000 --- 00 ---
1500 --- 00 ---
2000 --- 00 ---
2500 --- 00 ---
3000 --- 00 ---
3500 --- 00 ---
4000 --- 00 ---
4500 --- 00 ---
5000 --- 00 ---
5500 --- 00 ---
6000 --- 00 ---
6500 --- 00 ---
7000 --- 00 ---
7500 --- 00 ---
8000 --- 00 ---
--- ---

Screen 19: Pump
Pump1 Amt --- +15%
Pump1pulse --- +02
Pump1Trig --- +14
Pump1Stop --- 00"Hg
Pump2Start --- 2000
Pump2Amt --- +30%
Pump2Time --- +10
Pump2Trig --- +10
Pump2Stop --- 00"Hg
Pump1ADV --- +05
Pump2ADV --- +05

Pump Dwell --- 3.00
Pump Timers --- No
Pump1 Sync --- No
Pump Spare --- +10
PumpCold --- +00%



Screen 20: Water
-25 C --- +00%
-17 C --- +70%
-9 C --- +60%
-1 C --- +55%
5 C --- +50%
11 C --- +50%
18 C --- +45%
24 C --- +35%
31 C --- +30%
38 C --- +20%
46 C --- +15%
60 C --- +12%
68 C --- +08%
82 C --- +00%
99 C --- +00%
124 C --- +00%


Screen 21: Air_t
-25 C --- +00%
-17 C --- +08%
-9 C --- +06%
-1 C --- +05%
5 C --- +04%
11 C --- +03%
18 C --- +03%
24 C --- +00%
31 C --- +00%
38 C --- +00%
46 C --- +00%
60 C --- +00%
68 C --- +00%
82 C --- +00%
99 C --- +00%
124 C --- +00%


Screen 22: Crank
-25 C --- +72%
-17 C --- +72%
-9 C --- +72%
-1 C --- +67%
5 C --- +62%
11 C --- +57%
18 C --- +50%
24 C --- +41%
31 C --- +31%
38 C --- +26%
46 C --- +20%
60 C --- +15%
68 C --- +05%
82 C --- +00%
99 C --- +00%
124 C --- +00%

Screen 23: tºrpm
500 --- +00°
1000 --- +10°
1500 --- +15°
2000 --- +20°
2500 --- +25°
3000 --- +25°
3500 --- +25°
4000 --- +25°
4500 --- +25°
5000 --- +25°
5500 --- +25°
6000 --- +25°
6500 --- +25°
7000 --- +25°
8000 --- +25°
9000 --- +25°

Screen 24: tºmap
30"hg --- +00°
25"hg --- +05°
20"hg --- +04°
15"hg --- +03°
10"hg --- +02°
05"hg --- +00°
00"hg --- +00°
2 psi --- +00°
4 psi --- +00°
6 psi --- +00°
8 psi --- -02°
10 psi --- -03°
14 psi --- -04°
16 psi --- -05°
18 psi --- -06°
20 psi --- -06°


Screen 25: tºair
124 C --- +00°
99 C --- +00°
82 C --- +00°
68 C --- +00°
60 C --- +00°
46 C --- +00°
38 C --- +00°
31 C --- +00°
24 C --- +00°
18 C --- +00°
11 C --- +00°
5 C --- +00°
-1 C --- +00°
-9 C --- +00°
-17 C --- +00°
-25 C --- +00°


Screen 26: tºgap
500 --- +15°
1000 --- +15°
1500 --- +15°
2000 --- +14°
2500 --- +12°
3000 --- +10°
3500 --- +10°
4000 --- +10°
4500 --- +10°
5000 --- +10°
5500 --- +10°
6000 --- +10°
6500 --- +10°
7000 --- +10°
8000 --- +10°
9000 --- +10°

Screen 27: tºInj
500 --- 120
1000 --- 150
1500 --- 150
2000 --- 150
2500 --- 150
3000 --- 150
3500 --- 180
4000 --- 180
4500 --- 210
5000 --- 210
5500 --- 210
6000 --- 240
6500 --- 240
7000 --- 270
8000 --- 270
9000 --- 270

Screen 28: tºwat
124 C --- +00°
99 C --- +00°
82 C --- +00°
68 C --- +00°
60 C --- +00°
46 C --- +00°
38 C --- +00°
31 C --- +00°
24 C --- +00°
18 C --- +00°
11 C --- +00°
5 C --- +00°
-1 C --- +00°
-9 C --- +00°
-17 C --- +00°
-25 C --- +00°


Screen 29: Aux
RPM_ON --- OFF
MAP_ON --- OFF
FAN_ON --- OFF
FANadd --- 0.10
FANair --- 0.10
AIRmin --- 10.00
AIRmax --- 10.52
AIRwat --- 0.48
AIRafs --- 0.10
RMPset --- 0880
pwmLOW --- 0.76
pwm_HI --- 7.62
RMPlim --- OFF
AIRadd --- 0.19
Enrich --- 0.00
Timing --- +00

Screen 30: Opt
---- --- Is now --- Was
MixTrm --- -21% --- 00
TPScal --- +36% --- +24
TimTrm --- +00
Static --- +00
TIMmax --- +30
RPMwot --- 05"Hg
RPMcrs --- 17"Hg
AF_ste --- +10%
RevLim --- 7000
RevCut --- 7500
BstCut --- 12psi
IdlMap --- ---
RevStg --- 3000
MapStg --- 05"Hg
%Stg --- +50%
Decel --- OFF
Dwell --- +48% --- 3.25


Screen 31: Setup
---- --- Is now --- Was
Maps --- Matrix
Config --- +01 Cyl/R
Firing --- Sequential
LOAD= --- MAP sensor
DWELL= --- Duty Cycle --- TB
Input --- +POS
Spark --- Trig Maz+
Timing Check --- OFF
Rpm_ON --- 3500 Log
Map_ON --- OFF Log
Trim #2 --- +00% Log
Trim #3 --- +00% Log
SHIFT --- 7500 Dash
WATER --- 99_C Dash
AIR_T --- OFF Dash
BOOST --- OFF Dash

The car has stock 550cc primaries and RC 750cc Secondaries. RB TurboII exhaust, Bonez hi-flow cat, Walbro 255, SX FPR, Innovate Wideband, LTX12s

Any input on this is greatly appreciated. Rx72c, what do you think? My next goals are

1. Correcting whatever is up with spark (if that isn't normal)
2. passing Colorado emissions test
3. developing 300hp

Thanks,000,000 to all

- kel -

 

At least you got it running

 

qoute


Screen 31: Setup
---- --- Is now --- Was
Maps --- Matrix
Config --- +01 Cyl/R
Firing --- Sequential
LOAD= --- MAP sensor
DWELL= --- Duty Cycle --- TB

config should be set to 4 not 1